00:02
Hi there.
00:03
In this question, we want to determine the molecular geometry of the polyatomic ion, n .o4, 3 negative.
00:14
Okay, so to detain its geometry, what we need to do is write its lewis structure, because that way we can see how many atoms are bonded to the central atom, and we can see how many lone pairs there are on the central atom.
00:27
All right, so to write the lewis structure, first thing we need to know is how many valence electrons we have to work with.
00:35
So not, nitrogen is in group 5a of the periodic table, so it has five valence electrons.
00:41
Then we have four oxygens.
00:44
Each oxygen is in group 6a.
00:47
So each oxygen has six valence electrons.
00:51
And then this ion has a three negative charge.
00:54
That means it has gained three electrons.
00:57
So we have to add those in as well.
00:59
So adding these together, we have five plus four times six is 24.
01:04
So five plus 24 is 29.
01:07
Plus three gives us 32 valence electrons.
01:14
And in a lewis dot structure, valence electrons are represented as dots.
01:18
So that means our completed structure needs to have exactly 32 dots.
01:24
All right, let's go ahead and sketch this out.
01:27
The single atom will go in the center, so that is nitrogen.
01:31
It's going to be surrounded by the four oxygen atoms.
01:36
We know there has to be at least a single bond holding each...