00:02
Hi there.
00:03
To start off this question, let's look at the periodic table and just remind ourselves of the number of valence electrons that elements in the main group elements will have.
00:12
So all of the elements in group 1a will have one valence electron.
00:17
All of the elements in group 2a have 2.
00:20
All of the elements in group 3a have 3a have 3 valence electrons.
00:23
4a they have 4, and 5, 6, 7.
00:28
And except for helium, that only has 2, because it only has one energy level, all of the other noble gases have eight valence electrons.
00:37
Okay, so in this question, we have a sodium cation.
00:43
So sodium is right here.
00:44
As an atom, it has one valence electron.
00:49
To form the ion, to form a cation, it is going to lose that one valence electron that it has.
00:56
So it will end up with a positive charge.
00:59
When it loses that one electron, it had 11 electrons.
01:03
Now it only has 10.
01:05
So it now has now has the same configuration as neon.
01:11
So we want to see which of these four choices as an ion would have the same configuration as neon.
01:22
All right.
01:23
So our choices, we have chlorine, we have oxygen, calcium, and rubidium.
01:37
Okay, let's start with our positive ions first, our ones that are going to form cat ions.
01:44
Ribidium is just like sodium is going to lose one electron.
01:48
When it does, it will end up with the configuration of krypton...