00:01
Hi there.
00:02
In this question, we are trying to determine which of these electron configurations are correct, and it can be more than one.
00:10
So let's go ahead and get started.
00:11
What i'm just going to do is reproduce these ourselves and see if they match.
00:16
There are several ways you could do this, but i'm just going to write it ourselves and see if it matches.
00:22
So our first one is rabbidium.
00:25
So when we are writing a condensed configuration, we go to the noble gas in the period before.
00:32
So that would be krypton.
00:35
And putting that in brackets represents all of the core electrons.
00:40
So in other words, the first 36 electrons.
00:43
So all we need to do now is write that one more electron that this has.
00:49
And it's in the first group of the periodic table.
00:51
And everything in the first group of the periodic table ends with an s1.
00:55
And if we look to the left, it's in period 5.
00:59
So it should be 5s1.
01:01
All right, now we're going to look to see if it matches, and it does not because they have 4s1 incorrectly.
01:11
So ribidium is incorrect.
01:15
Let's go to m .g with a 3 plus charge.
01:21
Magnesium is normally atomic number 12, which means it normally has 12 electrons.
01:28
But it has a 3 plus charge, so that means it has lost 3 electrons.
01:34
And now only has nine electrons, which means it is going to be isoe electronic or have the same configuration as flooring.
01:46
Okay, so let's go ahead and write the configuration for magnesium with a three plus charge.
01:53
And remember, it's just going to be like flooring.
01:55
So if we look at flooring, here's flooring because magnesium has lost one, two, three electrons.
02:07
So it's flooring.
02:09
So we go to the noble gas in the period before, which is helium.
02:15
And we put that in the brackets.
02:17
Then we move across the second period.
02:20
So this is in the second period.
02:22
So we fill in the s.
02:25
So we have 2s2.
02:29
And then we see that flooring is in p5.
02:32
Remember these are the p block elements.
02:35
They end with p1 through p6, with the exception of helium, of course.
02:42
All right, so then it's going to be 2p5.
02:46
Let's check what they have there.
02:47
Ah, that is what they have there...
