00:02
So, valence electrons are defined as electrons in the outermost orbital of an atom.
00:09
There are electrons that are transferred or shared in order to form bonds between atoms.
00:17
So for representative elements, the number of valence electrons of an element is equal to the group number.
00:26
So let's go over why that would be.
00:28
So the first one we're looking at is aluminum.
00:32
Aluminum is in group 3a or group 13.
00:36
Usually, when we have aluminum, we will see aluminum written as al3 plus if it's an ion.
00:48
So that shows it loses three electrons in order to form the ion.
00:57
So atoms will lose their valence electrons in order to form ions.
01:05
Since it forms an ion with 3 plus, it loses three valence electrons.
01:09
So it has three valence electrons as indicated by the group number three.
01:21
So this is assuming we're looking at this group number 3a.
01:27
So we can also look at it as 13, but we'd have to subtract 10 from that to get the number of valence electrons.
01:36
Now let's look at strontium sr.
01:38
So this is in group 2a.
01:41
So when we have the elements in group 2a, they will always 4.
01:46
Ions with a charge of 2 plus.
01:52
That means they lose two valence electrons in order to form the ion.
02:04
Now for potassium, it is in group 1a.
02:07
So it is going to lose its long valence electron to form k plus to a positively charged ion.
02:15
Then we have bromine that is in group 7a...