<span>Most molecules containing carbon are organic. All organic compounds, from basic elements through complex living creatures, contain some degree of carbon, which is one of the most basic components of any organic molecule.</span>
I believe the correct answer would be the last option. When an electrons moves from an excited state to the ground state, it would release energy. An electron in the excited state would mean that it contains high kinetic energy so to move to a lower state some of these energy should be released.
Lithium sulfide (Li2S) would have 2 lithium atoms for every sulfur atom and would form an ionic bond. Sodium oxide (Na2O) has 2 sodium atoms for every oxygen atom (same ratio) and forms an ionic bond.
