Question

The electron configuration of an element is 1s2,2s2,2p6,3s2,3p3. How many valence electrons does this element have?

Answer 1

Answer:

5

Explanation:

The first step is to fine the element on the Periodic Table. Going through the configuration, the element seems to be Phosphorus (P). Now that we know where the element is, we can count from the left until we reach our element. The first column is all the way on the left and starts with the element Hydrogen (H). Every element in that column has a valence of 1. Each column to the right of it increases by 1. Doing this, we can find that Phosphorous has a valence of 5. I hope this helps!