Calcium and chlorine combine to form $CaCl_2$,but they do not form $CaCl$. This is because:

• A
  Removing one electron from calcium requires less energy than removing two electrons.
• B
  More energy is released when a chlorine atom forms a chloride ion during the formation of $CaCl_{2(s)}$ compared to $CaCl_{(s)}$.
• C
  The lattice energy of $CaCl_{(s)}$ is less exothermic than that of $CaCl_{2(s)}$.
• D
  More energy is released when $CaCl_{(s)}$ is formed from its elements compared to $CaCl_{2(s)}$.