Question

Along each row of the periodic table,

A.
atomic mass increases from left to right.
B.
atomic mass is the same for all elements in the row.
C.
atomic mass changes in no set pattern.
D.
atomic mass decreases from left to right.

Answer 1

The correct answer is A, atomic mass increases from left to right.

Atomic mass increases from less to right as each element contains more protons and neutrons.