Metallic bonding is... a
a type of covalent bond.
b
a type of ionic bond.
c
an attraction between positive and negative ions.
d
an attraction between positive ions and electrons.

Ais the correct answer

Spontaneity tell us the direction of the reaction, but not how fast it goes. gibbs free energy brings together enthalpy, entropy and temperature in one easy formula. g = h - ts. and, finally the sign of delta g is always negative for a spontaneous reaction.

The mass has escaped into a gas which you can not see so the law stays true.