Why reaction between alkali metals and water exothermic?

[terryds]

Why the reaction between alkali metals and water exothermic??
I know that it produces heat to surroundings
But, what actually happens?? Why it gives heat to surroundings??

http://antoine.frostburg.edu/chem/senese/101/thermo/faq/exothermic-endothermic-examples.shtml says that when forming ion pairs (like ionization reaction), it is endothermic (since it needs some heat to get the electron out)

But, the reaction between alkali metals and water is

2M(s) + 2H2O(l) => 2M+(aq) + 2OH−(aq) + H2(g)

Which forms ions pair..
But, it's not endothermic, but exothermic.. Why?

 

[Borek]

Cation hydration is strongly exothermic.

 

[James Pelezo]

2Na^o(s) <=> 2Na⁺(aq) + 2e^- E^o = -2.71 volts
H₂O(l) + 2e^- <=> 2OH^-(aq) + H₂(g) E^o = -0.83 volts
2Na^o + 2H₂O(l) <=> 2Na⁺(aq) 2OH^- + H₂(g) E_net = (E_redn - E_oxdn = [(-0.83v) - (-2.71v) = 1.88v (net)

∆ G = - nFEo = -[(2e-)(96,500C)(1.88v) = -362,840 joules = - 363 Kj

Compares well with Heat of Formation Tables using Hess's Law
ΔH_rxn = [∑ΔH_f(P) - ΣΔH_f(R)] = [2mole(-240.1Kj/mole) + 2(-230.0Kj/mole)] - [-(2(285.8 Kj/mol)] = - 368.6 Kj
⁴
A common 1" diameter Parraffin wax candle will gives off about 4x more heat than in this lab study;i.e., ~ 1.2 x 10 ⁴ Kj/mole wax.