The maximum number of electrons allowed in the fourth energy level of an h atom is

The fourth energy can hold up to 32 electrons, 2 in s orbitals, 6 in p orbitals, 10 in d orbitals,and 14 in F orbitals 

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.