What do a mole of magnesium (Mg) and a mole of iron (Fe) have in common? A.
their number of atoms

B.
their number of molecules

C.
their number of electrons

D.
their number of protons

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.

Can someone me with questions 12 and 13 plz.

What is the correct name for the compound cocl3? a) cobalt(i) chloride b) cobalt(i) chlorate c) cobalt(ii) chlorate d) cobalt(iii) chloride