in this lesson we will learn about What ions are and how they are formed when an atom gains or loses electrons they develop a charge recall that electrons are negatively charged so the gain or loss of electrons will create a charge these charged particles are called ions when an atom loses electrons they become positively charged positively charged ions are called cat ions easy way to remember this is to recall that cats have pause when an atom gains electrons they become negatively charged negatively charged ions are called anion let's look at sodium as an example its electronic structure is 2 8 and 1 it has one electron in its veence or outermost shell when sodium loses this veence electron it becomes a positively charged sodium ion this charge is written as a superscript when writing the symbol when drawing the electronic structure enclose it in square brackets and write the charge on the top right hand corner now let's look at oxygen as another example its electronic structure is 2 and six six therefore there are six electrons in its veence shell oxygen gains two electrons to form a negatively charged oxide ion remember to include the charge when writing the symbol and when drawing the electronic structure if we look at the electronic structure of these two ions we will see that they have a complete outer shell we will also see that they have the same electronic structure as that of a noble gas the sodium ion and the oxide ion have the same electronic structure as the neon atom how are you feeling about ions are you ready to form ions on your own let's try please pause the lesson and draw the electronic structure of a calcium ion and a chloride ion the electronic structure of calcium is 2 8 82 it loses two veence electrons to form a calcium 2+ ion the electronic structure of chlorine is 2 8 and 7 it gains an electron to form a chloride ion these two ions have the same electronic structure as an argon atom did you get the structures right and did you remember to specify the charges what do sodium and magnesium ium have in common they are both metals and metals lose their veence electrons to form catons group one Metals such as sodium have one veence electron and they lose this electron to form ions with a plus one charge group two metals such as magnesium have two veence electrons and they lose these electrons to form ions with a two plus charge oxygen and Florine are both non-metals non-metals tend to gain electrons to form annion oxygen is in group six and has six veence electrons it gains two electrons to form an ion with a -2 charge Florine is in group seven and has seven veence electrons it gains one electron to form an ion with a negative one charge group three elements such as aluminum lose three electrons to form ions with a positive three charge group five elements such as nitrogen gain three electrons to form ions with Nega -3 charge group four elements such as carbon tend to form coent compounds stay tuned in conclusion an ion is a charged particle formed from either the gain or loss of electrons a positively charged ion is known as a cation and a negatively charged ion is known as an annion the ions formed have the same electronic structure as their nearest noble gas