All atoms of a given element contain the same number of protons and the same number of neutrons?

No, the correct ans would be proton number equals to electron instead of neutron

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.