Which of the following is a true statement regarding the periodic table?

A. Atoms in the same group have the same number of electrons.
B. Elements are grouped according to their total number of neutrons.
C. Atomic mass decreases as you move left to right across the periodic table.
D. Elements with the same number of valence electrons are arranged in columns.

Respuesta :

D except for the transition metals copper iron tantalum etc they have different oxidation states so arent fixed shells but all main group elements are grouped by the valence electrons sodium potassium lithium alkali column 1 valence electron highly reactive.