Question

What is the sign of the enthalpy term in an ionization reaction?

Answer 1

Given the current conventions, they should be POSITIVE........

Explanation:

Consider the ionization reaction......

`"Atom(g)"` `rarr` `"Atom(g)"^+ + e^(-)`

We separate an electron from a positively nucleus. Reasonably, energy should be required to do this. And so we could rewrite the reaction to reflect this, i.e.......

`"Atom(g)"+Deltararr"Atom(g)"^(+) + e^(-)`

So given that this is an endothermic reaction, `Delta` should be POSITIVE........