what's going on bessies today we're going to be talking about ait's version 7 science more specifically chemistry and we're going to be starting with basic atomic structure let's get started so let's di deeper into the structure of atoms which are the fundamental building blocks of all matter so here we have an enlarged depiction of what an atom actually looks like although it's not an exact replica of what an atom looks like it serves our purpose for understanding in this particular moment of the te's so at the heart of an atom lies our nucleus which contain two different kinds of tiny particles we have our blue circles which illustrates our protons and we have our red circles which illustrates our neutrons this nucleus sits centrally in the middle of our atom and surrounding that nucleus we have these little yellow balls these little yellow balls actually represent the electrons that Circle our nucleus the these electrons move a long paths as I've outlined with these ovals here on your screen and this indicates that they're always in constant rapid motion around the nucleus electrical charge also plays a critical role in the behavior and structures of atoms so protons possess a positive charge think p and proton p is positive each has a charge of plus one whereas electrons carry a negative charge each with a charge of negative one neutrons in contrast actually carries no charge at all so when you think neutral think n neutrons and a neutral this aligns well with their names this interaction between positive and negative charges is fundamental to the atomic structure as we all know Opposites Attract each other which is vital for maintaining that Integrity that we see with atoms despite our electrons moving at high speeds around the atom they don't NE Escape into space because of that positively charged proton attracting that negatively charged electron effectively keeping them within that atom however what's good to know is that electrons move too swiftly to actually be pulled into direct contact with those protons hence they orbit around that nucleus rather than colliding inside of it it's also important to note that the number of protons and electrons are equal so atoms are electrically neutral particles neutrons despite being uncharged are significant in the stability of the nucleus they act as a binding force that helps maintain the nucleuses Integrity by mitigating those repulsive forces between the positively charged protons thus keeping our nucleus together another critical aspect of atoms besides electrical charge is their Mass understanding an atom's mass involves examining the mass contributions of the protons neutrons and electrons with most of that mass being concentrated inside the nucleus protons and neutrons are very similar in size and mass each weighing approximately this tiny little amount in grams it's a figure so small that it's best expressed by a scientific notation to simplify it recognizing the impracticality of such a small number scientists actually introduced the atomic mass unit as a more manageable measure when we're measuring atoms because of this both protons and neutrons are going to weigh approximately one atomic mass unit in contrast an electron is significantly lighter than our protons and our neutrons it only actually weighs about 0.549 atomic mass units this minute mass is a mere fraction of that of protons and neutrons when we're discussing the mass of an atom we're generally summing up the atomic mass units of our protons and our neutrons as they substantially contribute to the atom's total mass electrons due to their weight are typically disregarded whenever we're considering mass calculations of atoms similar to how you wouldn't account for the weight of a ring or maybe even a necklace when you're weighing yourself both of these items are going to be too light to impact the overall measurement significantly when you examine the periodic table each element is going to be assigned a specific box that contains two important numbers your first number is your atomic number and your second is your atomic mass your atomic number indicates the number of protons that are found in the element this number is consistent across all atoms of a particular element distinguishing each element from others for instance hydrogen has an atomic number of one indicating that it only has one proton whereas with oxygen the atomic number is eight reflecting that there are eight protons in oxygen the second number you are going to encounter is your atomic mass and this tells us how many protons and neutrons we're going to find in an element a simple pneumonic that I use to remember the differences between atomic mass and atomic number is Pan Man starting with our first part pan that stands for P is for protons A is for the atomic number and n is for the number of protons and then the second piece with man we know that m stands for our mass number a stands for ADD and n stands for our neutrons knowing both the mass number as well as the atomic number of an element allows us to determine the number of neutrons we're going to find in the nucleus of an atom to find out how many neutrons oxygen has this can be rearranged into the following formula neutrons is equal to mass number minus our atomic number so if we use this with our oxygen example we know that our atomic mass is 16 and our atomic number is eight if we minus those together it lets us know that we have a total of eight protons as well as eight neutrons so moving on to Isotopes this is a concept in chemistry that's frequently mentioned but not always easily understood so let's discuss this with a car analogy let's say that we have a fictional car brand called the catrona which epitomizes luxury and is celebrated for its distinctive style for this example let's imagine that the catrona are shaped like citrus fruits the catrona is going to come in three different distinct Brands we're going to have the catrona C the catrona CX and the catrona cxl each model is available in different colors and features unique options so the catrona C might have a basic radio and leather seats and it's also yellow the catrona CX might actually have chrome wheels and a CD player and it's painted blue while our luxurious red catrona cxl is going to feature massaging seats and platinum spinner Wheels the key Point here is that despite the variations in colors and features they're all the same kind of car they're all catrona like we talked about before they all share that same distinctive citrus-like shape this common characteristic is ultimately what defines the catrona regardless of the specific model or their options this is very similar to what we see with isotopes Isotopes are atoms of the same element that have the same number of protons but a different number of neutrons they all have different masses like the different features in each one of our car models but chemically they're all the same element now let me introduce you to three isotopes of carbon so we're going to be primarily focusing on our nucleus here represented by our red and our blue dots in the middle these swirling circles that you see along our atom here actually symbolizes our electrons but they're not the main concern when we're trying to figure out Isotopes the three isotopes that we have is carbon 12 carbon 13 and carbon 14 in carbon 12 if we count these little blue dots we're going to find that we have six protons and if we count each one of these little red dots we're going to see that we have six neutrons this is a classic example of what carbon is moving on to carbon 13 we still have six of our little blue dots meaning we still have six protons but what's different here is we have an additional Red Dot so now we have seven neutrons and lastly with carbon 14 we're seeing the same thing we still have six of our little blue dots meaning we have six protons but now we have two extra dots right now we have eight neutrons what do all of these forms have in common when it comes to carbon each isotope has six protons in its nucleus which defines it as carbon just like we saw with our a example whether an isotope has six or seven or eight neutrons it still has the same characteristics of carbon these variations don't change the element's fundamental identity therefore what we're dealing with here is we have various forms of carbon Isotopes different forms of the element have the same number of protons but they're going to have differing numbers of neutrons let's pause to have a better understanding of how these numbers are going to work when we talk about carbon 13 and carbon 14 so starting off with our carbon 12 we know that when we look at the periodic table this is usually what we're going to see when it comes to carbon we are going to have an atomic mass of 12 and an atomic number of six that six lets us know that each one of these atoms has to have six protons in order for it to be identified as carbon this is true for every single one of our examples the only difference is is that our mass changes a little bit as we move down with the additional neutrons this first example is a classic unit of carbon right this example here means that our atomic mass is a little bit more than the standard carbon instead of it being 12 it's now 13 so that lets us know there's one additional Neutron inside of our atom just the same way as we see with 14 14 is just going to be slightly bigger than r13 and it's just going to let us know that we actually have two additional neutrons instead of one like we saw with 13 so that is how we determine not only what the element is but what the weight is depending on how many neutrons are found inside that element so let's talk about ions what exactly is an ion it's a common term in chemistry so let's break it down a little bit to understand it an ion is simply an atom or a group of atoms that carries an electrical charge so exactly how does an atom become an ion in the nucleus of our atom we have protons and they possess a positive charge and surrounding that nucleus on the outside we have electrons which carry a negative charge typically an atom is going to have an equal number of protons and electrons resulting in no overall charge however an atom can become an ion if it gains or loses electrons so if an atom gains an extra electron it's going to become more negatively charged than positive becoming a negatively charged ion conversely if it loses electrons it will have a more positive charge due to the excess protons thus becoming a more positively charged ion this imbalance in the number of protons and electrons results in the atom becoming an ion let's start by looking at our sodium atom in this illustration you'll notice that our protons are in blue and our electrons are going to be in the outside of our atom circling that that nucleus and they're going to be yellow while I've emitted neutrons which reside here in our nucleus they're not crucial in our current discussion since they don't actually carry any kind of charge and therefore they don't influence the electrical properties of an atom typically a sodium atom contains 11 protons and 11 electrons resulting in a net charge of zero this makes sodium atoms neutral however what sodium can do is it can lose electrons and when it does that Dynamic is going to change for instance if our sodium loses one electron which is transferring one electron from an atom to another that sodium now has 11 protons and only 10 electrons this imbalance results in a net positive charge making the sodium atom an ion with a charge of + one to indicate that the sodium atom is in a Charged State we denote sodium ions as n A+ in contrast a neutral sodium atom is going to be noted as just na this positively charged ion or cat ion as we like to call it exemplifies what happens when an atom loses electrons and gains a net positive charge thus our na+ is a prime example of a cat ion which is a type of ion that carries a positive charge a simple and effective way to remember what a cat ion is is we use the catchy pneumonic cat ions is a positive ion think of a cat with P to help you recall that cat ion sounds a lot like cat and ion put together it helps carry a more positive charge much like a positive feeling a cat's paws can bring now let's consider another example an atom of oxygen this illustration shows that we have eight protons and eight electrons orbiting around it the balance between protons and electrons means that oxygen is a neutral atom and has a net charge of zero so the funny thing about oxygen is it loves to gain and lose electrons in this scenario oxygen is actually going to gain two electrons now with this addition our protons in the nucleus are going to remain the same but now we're actually going to have 10 electrons on the outside of our nucleus surrounding it this surplus of electrons is going to result in that balance again creating a net negative charge due to those two extra electrons compared to our protons this oxygen atom now has a net negative charge of 2 minus when we represent this Ion with a symbol we're actually going to indicate o raised to the power of 2 negative to indicate that there is two negative charges in contrast we're just talking about a regular oxygen atom that hasn't made any changes we just denote this with an o this negatively charged ion is known as an an ion it's a term for ions that have more electrons than they do proton meaning that they have more of a negative charge to easily remember that an an ion is a negatively charged ion we use the pneumonic an anion is a negative onion now I know I said that a little bit funny but it's just to help with the neonic I want you to picture an onion with negative feelings characteristics symbolized by a Nega charge like we see with an an ion let's dive into the concepts of shells subshells and orbitals according to B's atomic model electrons orbit the nucleus along fixed paths which he termed shells or energy levels these shells are going to be denoted by the variable n so for example our first shell is going to be denoted by n equals one this is also known as our kshell our second level is going to be n = 2 that's going to be our L shell the next one's going to be n is equal to 3 that is our mshell and the last one is going to be n is equal to 4 that is our n shell now let's discuss subshells so every shell is divided into subshells or sub energy levels denoted by the letters of s p d and f here is how the subshells are going to be distributed across different shells so starting with our first shell or ring or energy level whatever you want to call it we have n equals 1 that's our kshell we're going to see only one subshell and that's going to be our s subshell moving on down to our Nal 2 that's going to be our L shell we're actually going to see two subshells we're going to see an S and we're going to see a p moving down to Nal 3 our mshell we're going to see three subshells we're going to see an s a p and a D subshell and then lastly our Nal 4 our very last one our n shell is going to have four subshells we're going to have an s a p a d and this time an F so let's take a closer look at how each one of these shells and subshells affects the orbitals that we see around our nucleus so what exactly is an orbital an orbital is a threedimensional space within an atom where an electron in a given subshell can be found so we've already discussed the first part of this concept we have our shell number and our subshell designation so we're already very familiar with that what is all this other stuff mean so this is how we find the number of electrons depending on what our atom is so right here you see here it says number of electrons we have shell one so we know that shell one only has an S subshell so found within that s subshell we can only have two electrons in that subshell so that means if if we have an atom that has only one ring or shell or energy level whatever you want to call it they're only going to be able to have a maximum of two electrons in that first shell and if the atits ask you how to define the characteristics of an S shell this is kind of what it's going to look like it's just a circular sphere so let's talk about our second shell number right that's our second energy level that's completely separate from our first so as we discussed we know that we are going to have a subshell of both S and P within the second energy level whenever the aits ask you what does it look like it's going to almost have this dumbbell-like appearance that is what you're going to see when we're looking at that second energy level and what's Happening Here is it's going to have a maximum of eight electrons found within that second energy level it's going to have an S and it's going to have a p now I want you to remember this is very important that this s shell is completely different from first shell so if you have an atom that has two shells shell one and shell two shell one is always going to have two electrons at most right that's the maximum but our second shell that subshell is going to have eight electrons at most it's going to have its own distinctive s shell that's separate from this first one so it's going to have two there and then you're going to have this pshell that's the second subshell that you're going to see when you are on on energy level two what's important to note that is any time as we move up in subshells when we go from s to P to D to F we're always going to add four to that next set of subshells so in this case if we had an atom that had two energy levels two shells or two rings we're going to see a maximum of 10 electrons total for that atom so now let's move on to our third shell so as we know we have an S we have a p and we have a d subshell and what this kind of looks like again the teas loves to test you on what these shells look like it almost looks like a fourleaf clover right so with our first shell it's more of a circle sphere our second shell looks more like a dumbbell and our third shell kind of looks like a fourleaf clover so how many electrons maximum can we have in that third shell well the maximum number we can have is 18 so again it's going to have an s a p and a d shell that are completely separate from shell one and shell two so its s shell can only have a maximum of two its pshell can only have a maximum of six and its D shell has a maximum of 10 so that when we add that together that's how we get our 18 maximum number of electrons and remember anytime we're moving up in shells we're just adding the number four in between next we're going to be moving on to Shell four we're going to have an s a p a d and an F shell now you don't really see what that actually looks like in regards to Shell shape like we see with the other ones it looks completely different depending on the atom it's going to be all kinds of different configurations so it's hard to really give you a prime example of what that is going to be but if you're asked on the test these are usually the three shapes that you're usually going to be tested on so how many electrons maximum can this fourth shell have well it can have 32 so again completely separate from anything that's happening within these first three levels our fourth level is going to have an S subshell of two a p subshell of six a d subshell of 10 and we're just going to add four to get our F subshell of 14 so the maximum number of electrons that this particular shell energy level or ring is going to have when it comes to number four is going to be 32 so let's break this down of what it's actually going to look like in an atom so from our example down here you see we have a MAG magnesium atom and it has an atomic number of 12 remember anytime that we have a neutral atom it's going to have the same number of protons as it does electrons so if we have atomic number of 12 we know we have 12 protons and we should also have 12 electrons so this is how it is going to look written out so our first shell is going to have a maximum of two electrons in that shell right we can't have any more so 12 minus 2 we're left with 10 so now moving on to to our second set of subshells we have a s and we have a p so the S is going to have two and the p is going to have six that means that that subshell for level two can only have a maximum of eight so we're going to see eight electrons in that second shell we have 8 + 2 gives us 10 we're left with two more electrons that have to go someplace so that goes into our third shell so our third shell we're only going to have one shell we're going to have an S shell right and that's where the final two electrons are going to sit so just to give you kind of an idea of how this is actually broken down this is what it is going to look like first shells are going to have two cuz it only has an S subshell the second sub second shell is going to have eight because it only has an S and a p subshell and the last shell is going to have two because we can only fit two that's what the remainder was into our last s shell so to bring this all home let's examine a model of carbon atoms so typically it's going to consist of six protons six electrons and six neutrons that is what we're observing right here so we have our six protons and neutrons right here in the middle and then we have our six electrons floating around on the outside in our rings and as we discussed before each shell is going to correspond to a distinct energy level and it's going to have a maximum capacity of electrons depending on the number of the shell so carbon has an atomic number of of six which means we have six electrons so we need to have some place to place those six electrons on the outside of our carbon so our first shell which is our s shell our first ring here our S subshell I should say is going to have two electrons within that subshell because that s can only hold a maximum of two and that's the only subshell that we have in the first energy level of our shell or our ring so with our second shell ring or or energy level whatever you want to call it we have an additional four electrons that we have to place someplace else we know that based on that second level that second shell we can place a maximum of eight electrons so we're doing good we know that the first s of our second layer subshell is going to hold a maximum of two electrons and then we only have two left those are immediately going to go into the P subshell of our energy level so so this is what a carbon atom would look like and how many shells that they would have as well as subshells so during chemical reactions only the electrons that are in the outermost shells are going to be the ones involved in chemical bonding so for atoms that possess only one shell or energy level achieving stability requires having at least two electrons for atoms that possess two shells for energy levels they are going to achieve stability only if they have 10 electrons two found within their first shell and the remaining eight found in their second shell so let's finish off by examining our last two examples so first we're going to look at Helium which possesses just one shell or energy level and we find that it is complete with two electrons so helium is considered stable it does not form any naturally occurring compounds in contrast hydrogen also only has one shell but that one shell contains One Singular electron because as we see up here our atomic number is one that means we're only going to have one electron so this actually renders it chemically reactive a substance's reactivity is a chemical property best defined as its ability to interact chemically with a second substance still there's only one electron found in that s shell so for it to achieve stability it needs to gain at least one addition electron in that first shell so how is this achieved it's achieved through ionic and calent bonds so chemical bonds form when two or more atoms interact primarily through their outermost shells or energy levels these interactions often lead to chemical reactions especially in atoms that do not have eight electrons in their outermost shells atoms may lose gain or share electrons to satisfy the octet rule which states that they prefer to have at at least eight electrons in their valence shell this octant rule is the driving force behind the formation of various structures like crystals or molecules this is achieved through two main types of bonds ionic and calent ionic bonds involve the transfer of electrons between atoms let's explore how ionic bonds form with an example of sodium and chlorine sodium has an atomic number of 11 which means that it has 11 protons and 11 electrons the distribution of those electrons are as follows our first shell is going to have two our second shell is going to have eight and our third shell is going to have one chlorine has an atomic number of 17 meaning that it has 17 protons and 17 electrons its electrons are going to be distributed as follows the first shell is going to have two the second shell is going to have eight and its third shell is going to have seven to achieve that St stable octet sodium can donate its single outer electron thus attaining a stable configuration of eight electrons and it's now outermost shell chlorine in turn accepts that electron filling its outer shell to reach its desired eight electrons this transfer completes both the atoms quest for stability per that octet rule when that sodium atom relinquishes that electron it's left with 11 protons which is positively charged and now 10 electrons which are negatively charged this is going to cause that imbalance resulting in the creation of a sodium ion that carries more of a positive charge on the other hand the chlorine atom receives an electron bringing its composition to 17 protons and 18 electrons this excess and electrons is going to form a chloride ion with a negative charge the newly formed positively charged sodium ion is then attracted to the negatively charged chloride ion leading to the formation of sodium chloride also known as table salt this attraction and resulting bond is known as an ionic bond characterized by the transfer of electrons that result in the creation of two oppositely charged ions an easy way that I remember ionic bonds is I take you give ionic bonds form when one atom takes electrons from another like a transaction where one gives you money and the other one receives it next up we have calent bonds so calent bonds are chemical bonds where two atoms share one or more pairs of electrons within their outer shells this type of bonding is typical among four major elements found within our body we have carbon oxygen hydrogen and nitrogen as they tend to form coal bonds by sharing electrons so for example like we shared before two hydrogen atoms can form a bond by sharing a pair of electrons hydrogen is an exception to that octet rule which usually States an atom prefers to have at least eight electrons in its outermost shell and this is just simply because hydrogen only has one electron in its one shell so let's consider carbon dioxide CO2 to illustrate a calent Bond as we know oxygen has an atomic number of eight which means it's going to have eight protons and eight electrons two in its inner shell and six in its outer shell thus it needs two more electrons to complete its outer shell Carbon on the other hand has an atomic number of six meaning that they have six protons and six electrons two in its inner shell and four in its outer shell it's going to seek at least four additional electron in order to obtain stability here's where that Mutual benefit comes to play one oxygen atom can share two of its electrons with the carbon atom and in return the carbon atom shares two of its electrons with the oxygen atom satisfying our first oxygen atom similarly the second oxygen atom can also share two of its electrons with the carbon atom and again that carbon atom is going to reciprocate by sharing two of its electrons with our second oxygen atom this reciprocal sharing results in three atoms achieving a stable electron configuration in this case by sharing two pairs of electrons with each oxygen atom carbon forms double bonds which is crucial for chemical structures and reactions an easy way to remember calent bonds is sharing is caring C for Cove valent C for caring you can also think of a combination coworker however it is it will be easiest for you to remember it by using sharing is caring this phrase emphasizes that calent bonds involve sharing electrons equally or unequally but always involve some degree of sharing much like friends share responsibilities or tests lastly let's talk about the periodic table due to its complex structure and breakdown of atomic elements the periodic table really could be a video all on its own thankfully so far we've covered most of the information that you're going to need to know in order to pass the te's here's the additional information that we didn't cover about the periodic table so what is the difference between periods and groups those are two terms that you're going to need to know for your test that periodic table was an essential tool that was developed way back in the 1800s in order to organize chemical elements based on their atomic number and electron configurations upon examining our periodic table you're going to notice that we have seven horizontal rows these are known as periods each period is going to indicate the number of electron shells that an element is going to possess for example elements in the second period are going to have two electron shells well those down here in the sixth period are going to have six electron shells the vertical columns on a periodic table is referred to as groups elements within the same group share similar chemical properties the table features elements in groups numbered one all the way to 18 an alternative naming system for these groups uses labels like 1 a 2A we skip all of our transition metals right here in the center and it continues on from 3A all the way to 8A excluding helium each element in these groups typically have a number of veence electrons corresponding to its group number for instance elements found in group 2A are going to have two veence electron R well those found in group 7A are going to have seven most of our transition metals found here in the center are going to have either one or two veence electrons so in summary periods on the periodic table are going to be our horizontal rows and they are going to indicate the number of electron shells in contrast our groups which are going to be our vertical rows are going to reflect elements with similar chemical properties so let's do some practice questions question one States what occurs during the formation of an ionic bond is it a electrons are shared equally between atoms B electrons are transferred from one atom to another C protons are transferred between atoms or is it D neutrons are shared between atoms and the correct answer is B electrons are transferred from one atom to another ionic bonds form when one atom donates an electron to another creating ions of o opposite charges that are ultimately going to attract what statement best describes a calent bond is it a atoms share a pair of electrons B atoms transfer electrons to achieve stability C atoms gain electrons from another atom or D atoms donate electrons to a shared pool and the correct answer is a atoms share a pair of electrons remember with Cove valent bonds it's going to ultimately involve them sharing electrons between atoms typically between non-metals to fill an outer shell in order for it to achieve stability the octet rule primarily influences an atom's what the mass number the neutron number the electron configuration or the proton number and the correct answer is C electron configuration remember when it comes to that octet rule it states that atoms in order to achieve stability have to have at least eight electrons in it veence shell so it's going to ultimately directly correlate with the electron configuration what do all elements in the same period on a periodic table have in common is it a they have similar chemical properties B they have the same number of electron shells C they share the same group number or D they have identical atomic masses and the correct answer is B they have the same number of electron shells remember elements that are found in the same period are going to have the same number of electron shells with each period of the table adding an additional shell as we move from top to bottom I hope that this information was helpful in understanding everything you need to know about basic atomic structure if you have any additional questions make sure that you leave them down below I love answering your questions head over to nurse chunk store.com where there is a ton of additional resources to help you Ace those atit exams and as always I'm going to catch you in the next video bye