Which of the following statements about ionization energy is true?
a. in a period, elements farther to the right generally have lower ionization energies than elements on the left.
b. elements toward the bottom of a group periodic table generally have higher ionization energies than elements at the top of the group.
c. ionization energy is the amount of energy used to add an electron to an atom.
d. potassium has a lower ionization energy than sodium.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.