Question

How do you know the number of electrons in the outermost energy level of an atom?

Answer 1

Based on the periodic table

Explanation:

You look at what group the element is. Only works for groups 1,2,13-17.

ex boron is in group 13, it has 3 valence elevtrons (outermost level)

Florine is in group 17, so 7 electrons in the outermost level. etc