Question

A. On the Periodic Table of Elements, columns are called ______________________; all of these

Answer 1

1. Groups
2. They have the same number of electrons in their outer shell
3. Periods
4. They have the same number of shells

Answer 2

Answer:

A. On the peridic table of elemets, columns are called groups; all of these elements have the same number of electrons in the outer orbital.

B. On the periodic table of elements, rows are called periods; all of these have the same number of atomic orbitals.

I think this is right sorry if i'm wrong!