in this video I'm going to talk about the periodic table and certain properties of elements found in this table so let's go over the First Column Group 1 a in this group you have elements such as hydrogen lithium sodium pottassium rubidium and so forth now hydrogen is considered to be a nonmetal but the ones below it like lithium sodium and potassium these are considered to be Metals they're known as the alkaline metals they're very reactive if you put them in water they pretty much blow up now each of these elements in this column has one veence electron metals they like to give away electrons and they tend to form positively charged ions also known as cations so lithium sodium potassium as ions they're going to form a plus one charge now the next column is the group two elements they include burum magnesium Calum strontium and even barium so these are known as the alkaline earth metals they have two valence electrons and they form ions with a plus two charge the alkali metals group one they're the most reactive metals that we know of the alkaline earth metals they're also reactive but not as reactive as the alkaline metals then over here we have the transition metals I'm not going to write all of them but some transition metals are reactive others are not they vary but there's some common elements that you want to know such as zinc copper Fe stands for iron AG is silver Au is Gold PT Platinum HG Mercury so those are some common symbols that you want to be familiar with now we have other elements like boron carbon nitrogen oxygen Florine neon helium argon Krypton aluminum gallium silicon geranium phosphorus arsenic antimony tin lead sulfur selenium te chlorine bromine iodine Z on and so forth now group eight these are known as the noble gases helium has only two valence electrons the first R elements they can't have more than two electrons neon has eight valence electrons the noble gases are chemically inert for the most part they don't really react much so they're very stable the next group is the halogens which include Florine chlorine bromine and iodine these elements have seven veence electrons they're known as group 7A or group 17 on a prict table and they form negative one charges as ions the halogens are very reactive they're nonmetals but they're extremely reactive they're the most reactive nonmetals uh that we know of the next column are the cogens that's group 6A or group 16 of the periodic table and they have six veence electrons and they tend to form negative -2 charges nitrogen phosphorus arsenic those elements have five valence electrons and they typically form negative3 charges Boron aluminum gallium they have three valence electrons and they form plus three charged ions now the next group in the middle that have carbon silicon geranium they have four valence electrons but their charges can vary carbon and silicon they're typically you don't really see them in the an ionic form but the elements in group four they can form plus4 charges or plus two charges a good example is tin and lead tin has two o oxidation States the plus2 oxidation state and the plus4 oxidation state Le is the same thing it could be plus two or plus4 and then you also have some other elements over here which are known as the inner transition metals the first row represents the lanides and the second row is the actinides now in a preact table sometimes you might see a line that looks like this the elements that are very close to that line they behave as metalloids the elements on the far left so basically this entire group here that's the metals metals they conduct heat and electricity they're also malleable they could be hammered into sheets and they're ductile they can be pulled into a wire so you have Metals metals like to give away electrons so metals are electropositive as they give away electrons they form positive charges now the elements on the upper right side of the periodic table represent the nonmetals the nonmetals do not conduct electricity they're insulators and they like to acquire electrons the non-metals are electronegative as they acquire electrons they gain negative charges Florine is the most electr negative element on a periodic table on the other side below rubidium you have cesium and then below that francium francium is one of the most electropositive metals francium really likes to it really wants to give away an electron Florine really wants to acquire an electron so the two are opposite in their behavior now along the red line we have something called metalloids metalloids are like in between metals and non-metals they're not pure insulators like non-metals and they're not as good as Metals in terms of electrical conductivity Metals conduct electricity very very well non-metals do not conduct electricity at all metalloids they conduct a small amount of electricity some of the most common metalloids that you'll see in chemistry are silicon and geranium whenever you shine light on a metaloid or if you raise the temperature of a metaloid the electrical conductivity goes up if you increase the temperature of a metal the electrical conductivity decreases Metals become superconductors if you can cool them to a very low temperature close to absolute zero now another thing you need to know about the periodic table is the representative elements the representative elements include the elements that are not transition metals so elements that are not in this block or the inner transition metals those are not representative elements everything else are known as representative elements so group one group two group 13 to 18 or group 3A to 8A those are known as representative elements in the periodic table there's two numbers that are important that you should know so let's look at the symbol for floring which is f you'll see that there's two numbers a number nine on top and 19 below the element symbol the smaller of the two numbers represents the atomic number and the larger number is the average atomic mass you could simply say atomic mass the atomic number is always equal to the number of protons so Florine has nine protons the atomic mass represents the number of neutrons and protons so Florine has n protons 10 neutrons it adds up to 19 let's consider an atom of lithium lithium has an atomic number of three and if we average the mass number it's about seven so the number of protons that it has is 3 protons if you take the difference between 7 - 3 if you subtract the mass number and the atomic number you'll get the number of neutrons now in an atom the number of protons and electrons are the same an atom is electrically neutral so a lithium atom has three electrons if you draw it let's say this is the nucleus of lithium atom in the first shell it holds two electrons and in the second shell it has one electron the number of electrons in the outermost energy level represents the veence electrons so lithium has a total of three electrons it has one veence electron and two core electrons the core electrons are the electrons that are inside of the atom now within the nucleus of the atom which is here the protons and the neutrons exist in that location so the three protons and four neutrons they're inside the nucleus of the atom that's where most of the atom's mass is located is within that small tiny region of the nucleus the electrons so orbiting around the nucleus now here's a question for you you've learned from physics that like charges repel if you put two positive charges next to each other they're going to fill a force that's going to accelerate them away from each other but if you put a positive and a negative charge next to each other these two will experience a force of attraction so the nucleus which has protons which contain positive charges and neutrons which are neutral why don't the positive charges why don't they move apart aren't these two charges repelling each other so shouldn't they fly apart it turns out that the electric force that wants to separate the protons is balanced by another Force known as the strong nuclear force there's another force that keeps the protons and neutrons locked in together outside of that we have the electrons which are attracted to the the protons but the electrons are moving so fast around the atom and the force of attraction between the electrons and the protons it helps the electrons to stay in orbit around the nucleus so those are some basic principles that you want to be familiar with an atom but let's work on some problems finding the number of electrons and protons and neutrons inside an atom so keep this in mind the number of protons is equal to the atomic number and the number of neutrons is equal to the mass number minus the atomic number the number of electrons within an atom is equal to the atomic number minus the charge an atom is electrically neutral so it doesn't have a charge which means for atoms protons and electrons are the same but for an ion which has a charge the number of protons and electrons are unequal consider these two examples aluminum and the aluminum + three ion the atomic number of aluminum will always be 13 and the mass number is approximately 27 in the periodic table the 13 is on top but whenever you're dealing with whenever you write an isotope of an element that's elements with different Mass numbers but with the same number of protons or the same atomic number typically is written this way you have the atomic number on the bottom and the mass number on top but don't let it confuse you the smaller of the two is always the atomic number the mass number is the larger of the two numbers so how many protons does aluminum have the number of protons will always equal the atomic number to find the number of neutrons is the difference between the mass number and the atomic number so it's 27 - 13 so aluminum has 14 neutrons now the number of electrons will differ between an atom and an ion the number of electrons is the atomic number minus the charge an atom is neutral it doesn't have any charge so it's it's going to be 13 - 0 so therefore 13 electrons now for the ion it's going to be 13 minus the charge of three 13 - 3 is 10 so the aluminum ion has 13 protons and 10 electrons so we can see why the overall charge is positive3 if you add these numbers now one of the first quizzes that you may receive in your Chemistry course is a quiz on identifying the elements naming them or being able to identify a property of a certain element so I'm going to quiz you at this point so let's start with name and elements I'm going to give you a list of symbols and I want you to write down the names of each of these elements so what are the names of the five elements that you see here H stands for hydrogen C is carbon NE e is neon and is nitrogen SI silicon try these feel free to pause the video as you write the names of these elements F stands for Florine s is sulfur na is sodium K is potassium Fe is iron p is phosphorus Co is Cobalt CU is copper G is geranium CL chlorine a r is argon CA is calcium Al L is aluminum ni I is nickel C is chromium PD stands for Palladium Au is Gold AG is silver PT is platinum HG is Mercury and PB is lead asan is 10 SB is antimony h e is helium Li is lithium mg is magnesium MN is manganese so let's try some more examples for for okay I think that's good enough go ahead and name these elements pause the video try it and then unpause it when you're ready be is brillium RB Is Rubidium ba is barium s e is selenium I is iodine KR is Krypton X e is Xenon BR R is bromine a s arsenic V is vadium W tungsten CS cium RN radon GA a gallium B is for Boron n is for nitrogen O is for oxygen G is geranium U Is uranium ZN zinc CD cadmium TI titanium and watch out for TL that's uh theum now sometimes you might be quizzed on other questions relating to the elements so let's say if I give you a list of elements phosphorus selenium manganese chlorine and Krypton if I ask you which of these elements conducts electricity Which element would you select the correct answer is manganese manganese is a metal Metals conduct electricity the other four elements are non-metals they're insulators they do not conduct electricity now which of the following elements contains two valence electrons is it pottassium calcium gallium chlorine or sulfur so let's find the number of valence electrons that each of these elements contain pottassium is in group one of the prct table it's in the First Column so it only has one veence electron calcium is in group two so it has two valence electrons gallium is in 3A or 13 it has three valence electrons chlorine has seven sulfur has six so the answer is calcium now let's say if we have chromium strontium sulfur gallium and silicon which of of these elements is most likely to form a negatively charged ion also known as an anine is it chromium is it sulfur is it gallium which one is it so let's look at the charges that these elements like to form strontium is in group two so it likes to form a plus two charge gallium is in group 3A so it likes to form a plus three charge all of the metals typically form positive charges n Metals form negative charges so we're really looking for the non-metal chromium is a transition metal and transition metals they could form multiple charges chromium could be plus two sometimes it could be in the plus three oxidation state but it's not going to be chromium silicon is a metaloid and typically silicon usually forms positive charges as opposed to negative charges two common oxidation states are the plus2 and the plus4 oxidation state sulfur is a nonmetal and nonmetals like to acquire electrons so sulfur is going to form a Nega -2 charge it's in group 6A of the periodic table elements like oxygen sulfur cenum they like to acquire two electrons to form a negative two charge so now let's try another question so let's say if you're given the following elements bromine selenium geranium pottassium magnesium Cobalt and uranium so here's the first question which of the following elements are considered to be Metals Circle all of the elements that are metals so pottassium magnesium Cobalt and uranium are classified as Metals now which ones are non-metals bromine and selenium are non-metals G geranium is the metaloid now out of the elements listed which one is an alkaline metal the only alkaline metal that we have is potassium now which one is an alkaline earth metal the alkaline earth metals are found in the the second column of the periodic table and so magnesium is an alkaline earth metal now which one is a a transition metal and which one is an inner transition metal Cobalt is a transition metal but uranium is an inner transition metal uranium is part of the anide series now which element represents a halogen and which one is a calogen bromine is a halogen and selenium is a calogen which of these elements is the most reactive metal the most reactive metal includes The Alkali metal so that would be potassium which element represents the most reactive nonmetal the most reactive nonmetal is the hogen so that's going to be bromine and which of these elements do you think it's radioactive the one that's most likely to be radioactive is the heaviest one which is usually the inner transition metals the most heaviest element that we have here is uranium it has the highest atomic number elements with very high atomic numbers typically like 90 and above that most of them are usually radioactive so a lot of the elements that you see in the actinide series most of those elements are radioactive and uranium is one of them now which of these elements is chemically inert very stable is it phosphorus nickel chlorine argon or carbon the one that's most stable is the noble gas argon noble gases are chemically inert it's very very difficult for them to participate in a chemical reaction you need something very very reactive like Florine to make these elements react but for the most part they're chemically inert now which of these elements wants to give away electrons the elements that want to give away electrons are the metals the only metal that we have here in this list is nickel which is a transition metal so all metals they like to give away electrons rather than receive electrons now which of the following elements can conduct electricity so we know that Metals will always conduct electricity so nickel's one of them the rest are non-metals most non-metals as we mentioned before do not conduct electricity however there is one exception in this list and that exception is carbon carbon has many different forms or allotropes two common forms of carbon are diamond and graphite Diamond does not conduct electricity however diamond is an excellent conductor of heat graphite on the other hand because of its structure graphite is one of those rare nonmetals that actually do conduct electricity so the graphite form of carbon and nickel can conduct electricity now you need to be familiar with the elements and their physical States you need to know the seven diatomic elements hydrogen is diatomic nitrogen is a diatomic molecule the same is true for oxygen Florine chlorine bromine and iodine so these exists as diatomic molecules at room temperature hydrogen is a gas nitrogen is a gas and oxygen is a gas Florine is also a gas and chlorine is a gas bromine is a red liquid and iodine is a purple solid at room temperature now there's some other elements that you need to be aware of most metals are solid at room temperature however Mercury is one of those rare Metals that's a liquid at room temperature another element of interest is gallium at room temperature at about 25° celius gallium is a solid however if you raise the temperature slightly to around 30° C gallium will begin to melt into a liquid in fact if you put it in your hand the heat from your hand can cause gallium to melt into a liquid now this is all I have for this video hopefully you found it to be beneficial so thanks for watching and have a great day