Elements in these families are very reactive (x3)??

The Alkali Metals

As you move down the column, the metals become more reactive because the nucleus gains more electrons and protons (more electron levels), weakening their electrostatic force. Imagine that you're holding a bunch of books. You can't hold them all very easily, right? It's easy to drop one, which is why it's easy for them to donate 1 electron at STP.

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"