Question

Which two of these elements are in the same group of the periodic table.
A.Helium
B.Lithium
C.Sodium
D.Nitrogen
Give a reason for your answer.

Answer 1

B. Lithium and C. Sodium are in the same group because they are in the same vertical column on the table, which is considered to be a group.

Answer 2

The answer is B, Lithium and C, Sodium because they are in the same row in the periodic table

I've learned that a row, or column is called a group :)

Hope this helps, comment if this is incorrect