As you move from left to right across the second period of the periodic table, the a. ionization energy increases. b. atomic radii increase. c. electron affinity decreases. d. atomic mass decreases.

A would be correct. Have a nice day. :)

ionization energy increases.

Explanation:

As move from left to right

a) the atomic number increases but the number of shells remain the same hence the size of elements decreases (except noble gas).

b) Due to decrease in size the effective nuclear charge increases and this causes increase in ionization energy.

c) the electron affinity also increases on moving left to right

d) with increase in atomic number the atomic mass also increases.

So correct answer is

ionization energy increases.

i believe the answer is three water molecules