# How does the ionization energy vary across the Period?

Dec 12, 2016

You are saying that ionization energy increases across a Period, from left to right as we face the Table?

#### Explanation:

We examine the following reaction:

$M \left(g\right) + \Delta \rightarrow {M}^{+} \left(g\right) + {e}^{-}$

Going across the Period from left to right (facing the Table) the nuclear charge increases progressively with $Z$, the atomic number. Incomplete electronic shells shield the nuclear charge VERY imperfectly, with the result that ionization energy goes up substantially across the Period, and reaches a maximum at the end of the Period, at the Noble Gas.

Is this what you are after?