00:01
So here is our ion, 123 i minus.
00:08
So the first thing we need to do is, well, let's just list out what we need.
00:14
We need the number of protons, neutrons, and electrons.
00:22
So this mass number here will help us find the number of neutrons, and the charge here will help us find the number of electrons.
00:29
But the first step is protons.
00:35
And we need to do that by going to the periodic table.
00:38
So let's look for iodine.
00:41
It's right here.
00:42
When you see that it's number 53, so it's got 53 protons.
00:50
I'll do protons in red.
00:53
We know that it's 53 because the parent table told us that...