What is hydrogen classified as ?

Hydrogen is the most common element in the universe. Hydrogen is most often classified as a nonmetal because it has many of the properties of nonmetals. For example, it is a gas at room temperature. However, hydrogen shares properties with the alkali metals in group 1.

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.