00:03
Hi there.
00:04
In this question, we have an element, element x that forms a compound with chloride that is x, cl2.
00:13
And this is an ionic compound.
00:15
Well, the chloride ion has a one negative charge because it's a halogen, and all halogens have ions that form a one negative charge.
00:23
And there are two of those with x in this formula.
00:27
That means x must be an ion with a 2 plus charge, which tells us that when it formed an ion from its atom, from its element, it must have lost two electrons.
00:41
Because by losing electrons, a positive ion or a cation is formed.
00:46
Okay, so we know that this ion has 36 electrons.
00:55
Well, if it lost two, that means as an atom, it must have had 38 electrons as an atom.
01:07
And atoms are neutral.
01:09
So if it had 38 electrons, it must also have 38 protons.
01:15
Because it's going to have the same number of positive charges as negative charges to be that neutral atom.
01:22
So 38 protons means an atomic number of 38 because the number of protons equals the atomic number...