Periodic Table: Main Group Element Charges - Online Tutor, Practice Problems & Exam Prep

Periodic Table: Main Group Element Charges Concept 1

Now the elements of the periodic table will either lose or gain electrons to become just like the noble gases. Remember, your noble gases are the elements that are found in group 8A or group 18. So, there are two different ways to describe the same column of the periodic table. The reason these elements want to become like the noble gases is because noble gases themselves have the optimal number of outer shell electrons. What that means specifically, we'll talk about in several chapters from now, but just realize when it comes to the elements, they'll either lose or gain electrons so that their number of electrons matches one of the nearest noble gases.

When it comes to metals, metals tend to lose electrons to become positively charged ions called cations. Here, just think of it like this: cations at "t" could represent the positive charge that the ion gains. And it makes sense because if you're losing negatively charged subatomic particles in the form of electrons, you're going to become more positively charged. Now metals themselves can have either one type of positive charge or multiple types of positive charges. When a metal possesses one charge, we refer to them as type 1 metals. When metals have multiple charges, then they're referred to as type 2 metals. We'll go into greater detail on what types of metals are type 1 metals and what other types of metals are type 2 metals.

Now if metals lose electrons, then nonmetals must be gaining electrons. So nonmetals tend to gain electrons to become negatively charged ions called anions. Remember, again, this makes sense. I'm gaining negatively charged electrons, so I am going to become more negative as a result. So just remember, the whole reason elements gain and lose electrons is to become just like the noble gases. In the next video, we'll see exactly how many electrons we will lose or gain for any particular element.

Periodic Table: Main Group Element Charges Example 1

So for this example question it says, from what you know about ion formation in the periodic table, which ion would be unlikely to occur? So before we look at this question, remember, we're going to say that metals, they tend to lose electrons. So if they're going to lose electrons, they're going to become positively charged and remember, non-metals tend to gain electrons and therefore become negatively charged. So if we take a look here, we have Rb. Looking on a periodic table, we know that Rb is a metal, and therefore, it makes sense that it would have a positive charge. So this is a likely setup for an Rb ion. Next, oxygen. O, oxygen is a nonmetal. Non-metals tend to gain electrons and become negatively charged. So this is reasonable. Mn. Mn is a metal. Again, metals tend to lose electrons to become positively charged, so that positive charge is a possibility. Al. Al is aluminum. Aluminum is a metal. Again, metals tend to lose electrons to become positively charged. So it doesn't make sense that Al would have a negative three charge here. So this is unlikely. So this would be our answer. Then if we look at the last one, Cl, chlorine, chlorine is a nonmetal, so it makes sense it could gain electrons to become negatively charged. So just remember, metals tend to lose electrons to become positively charged, non-metals tend to gain electrons to become negatively charged. Now that we know this fundamental idea, let's move on to our next video where we go into how many electrons they gain, how many electrons they lose, and in that way, know what type of ions are possible for certain types of elements.

Periodic Table: Main Group Element Charges Concept 2

So let's talk about first our main group elements. Remember, your main group elements are the elements found in group 1A or group 1, 2A or group 2, and then from 3A to 8A, or what we call groups 13 to 18. The elements here in the grayed out box, those are our transition metals. We'll talk about those later on. But for right now, let's just focus on our main group elements. Now recall that the atomic number, which uses the variable Z, of an atom equals the number of protons within its nucleus. For example, we'd say that beryllium has an atomic number of 4, so it has 4 protons. For a neutral element, its number of electrons is equal to its number of protons. So beryllium here has an atomic number of 4, which means it has 4 protons, and here, if we're dealing with a neutral element, it'll have the same number of electrons, so it'll also have 4 electrons.

Now we said that all these elements of the periodic table are all trying to become just like our noble gases, our group 8A elements. They have the optimal number of electrons. Helium has 2, neon has 10, argon has 18, and as we go down, these are all their atomic numbers, which gives us the number of electrons they have. Now elements try to gain or lose electrons to match the number of electrons of the noble gases. So noble gases, since they're perfect, their charge is 0. So they don't have a charge. They don't need to gain or lose electrons. Let's look at group 7A, all the elements in group 7A.

Fluorine, let's look at F. Fluorine has 9 electrons when it's neutral. If it wants to have 10 electrons like neon, it would have to gain 1 electron. Chlorine has 17 electrons when neutral. To have 18 like argon, again, it would have to gain 1 electron. So each element in this column would have to gain 1 electron to become like the noble gas next to it. By gaining that one electron, they would get a charge now of minus 1, because, remember, gaining electrons gives us a negative charge.

Oxygen. Oxygen when neutral has 8 electrons, to have 10 electrons like neon, how many electrons would it need to gain? If you said 2, you'd be right. So same thing with sulfur, it has 16. It'd have to gain 2 electrons to become just like argon. So this group 6A, its charge is normally negative 2. Nitrogen has 7, so to get to 10 it'd have to gain 3 electrons. So the charge of this group is normally minus 3.

Now, of course, some of these groups it gets tricky because in group 5, we see that we have nonmetals here, so they have a negative 3 charge, but then we have metalloids, and then we run into metals. Metals don't wanna have a negative charge. They wanna have a positive charge. So these negative charges, when we're referring to them, is predominantly with the nonmetal, the elements that are in the blue boxes. Group 4 is a little bit tricky. So group 4 is equidistant either way. What I mean by that is carbon could try to gain 4 electrons to become like neon or it could try to lose 4 electrons so that it has 2 like helium. So it's kind of in a special situation. As a result of this, we kind of just say non applicable to group 4 based on the location in the periodic table.

Now, though, we do have an exception that that's around, exception 1, and this pertains to lead and tin, SnPb. Okay? Because of where they're located, how far down they are, they kinda have characteristics similar to transition metals. They can either be plus 2 or plus 4 for their charges. So just remember when it comes to tin and lead, they can be plus 2 or plus 4. They're interesting situations when it comes to the periodic table and charges.

Now let's look at boron and the other elements that are within this group. Boron is a metalloid. Metalloids, they have characteristics of both metals and nonmetals, so it's a bit tricky with them. So we won't be talking about boron, but we can talk about the elements below boron, aluminum all the way down to NH. They're all metals, so they all wanna lose electrons to become like a noble gas. Now aluminum here, its atomic number is 13. So when it's neutral, it has 13 electrons. It has 2 choices. It could either try to gain 5 electrons to have 18 electrons just like argon or it could do something easier than that. Instead of trying to gain 5 electrons, it could just try to lose 3 electrons, so that it has 10 electrons like neon. And when it comes to chemistry, we always go in the path that's easiest and fastest. Okay. So it's easier for aluminum to lose 3 electrons than to gain 5 electrons, okay, because there are more spaces that you have to jump to become a noble gas this way. Easier just to let go of your 3 electrons. So because of this, this group tends to be plus 3 for its charge.

Beryllium. Let's look at Beryllium. Beryllium has an atomic number of 4, so it has two choices. It can either try to gain 6 electrons to become like neon or do something easier. Just lose 2 electrons so that it has 2 electrons just like helium. So the easier and shorter path is to lose electrons. So this group tends to be plus 2.

Then finally, again, we're talking about the metals. They're the ones who wanna lose electrons to become positive. Hydrogen is not a metal, so we don't talk about hydrogen in this regard, but we'd say that lithium could try to gain 7 electrons to get to 10 like helium, which is a long distance to cover, or the easier thing would be just to lose 1 electron and become like helium. So this group tends to be plus 1.

So these are the charges that you need to commit to memory when it comes to these different groups. Group 1A plus 1, Group 2A plus 2, then plus 3. 4th group is not applicable. Group 5A is minus 3, then minus 2, then minus 1. Noble gases are perfect, so they don't want to gain a charge. Now exception 2, we're gonna say this pertains to our heavy metals of bismuth, polonium, and those that have atomic numbers from 114 to 118. Because of their position on the periodic table, they're a little bit weird and they have multiple types of charges, so we tend not to talk about them. But when it comes to main group elements, just keep in mind the major charges that we've listed, plus 1, plus 2, plus 3, minus 3, minus 2, minus 1, and then, of course, your exception 1. This is what you need to take away from the main group elements and their various charges.

Periodic Table: Main Group Element Charges Example 2

So for this example question, it's asking us to predict a charge that a gallium ion would possess. We know it has a charge because it's using the term ion. Now gallium, remember, gallium's element symbol is Ga. Gallium itself is in group 3a, or what we know as group 13. Now remember, in this group, it's easier to lose electrons because most of the elements in this group are metals, and it's easier for them to lose 3 electrons in order to be like the nearest noble gas. So here, this group 3a normally tends to be plus 3 in terms of charge. Because of this, option c would be our correct answer.