Question

along each row of the periodic table,
a. atomic mass is the same for all elements in the row
b. atomic mass decreases from left to right
c. atomic mass increases from left to right
d. atomic mass changes in no set pattern.

Explanation:

As you move from left - to - right across a period (row) in the periodic table, the number of protons and neutrons generally increases, leading to an increase in atomic mass.

Answer:

C. atomic mass increases from left to right