Question

Okay so I had this question on a test but I don't think any of the answers were correct. Can you please tell me if I am right?

Answer 1

The question is this:
Which of the following elements has five (5) valence electrons?

B

Rb

Mg

N

Answer 2

I don't think any of these are right

Answer 3

one of them is correct

Answer 4

it is?

Answer 5

what is a valence electron?

Answer 6

I thought the number of valence electrons was the number that is above each column

Answer 7

I think it is the electons on the outer ring right?

Answer 8

it is the number of electrons on the outer level. you need to "build" each atom's electron levels, then see which has 5 on the valence level

Answer 9

okay. How do I do that?

Answer 10

how many electrons can "fit" on each energy level?

Answer 11

I'm not sure :/ I know I learned it but I'm so tired right now I can't remember :(

Answer 12

You will see if they are right when you get your exam back. How about that?

Answer 13

I got my exam back yesterday (hence the past tense in my post) and it said my answer is wrong. I posted this question today because I am trying to understand why I was wrong And the test doesn't tell me which answer is correct, it only tells me if I chose the correct choice or not.

Answer 14

it is N

Answer 15

how though? I don't understand why it's N

Answer 16

because N has the atomic no. 7 and if we write its configuration 1s2 2s2 2p3 we get valency 5

Answer 17

oh okay :) Thank you!