00:02
Hi there.
00:03
In this question, we are being asked about the elements in group 2a.
00:08
So group 2a is here on the periodic table.
00:12
It is the alkaline earth metals.
00:16
So being that these are all metals, we know that metals lose electrons when they form ions to form positive ions known as cat ions.
00:34
All right.
00:35
So metals are going to lose electrons to form cat ions, so we know it's going to form a positive ion, and for the number of electrons it loses, we need to think about the number of valence electrons for the elements in this group.
00:48
So we know that this group, or these two groups, actually, are the s -block elements.
00:57
Everything in the first group 1a ends with an s -1, and everything in group 2a ends with an s -2.
01:05
So that means everything in group 2a has two valence electrons...