Why is the first ionization energy of aluminum lower than the first ionization of magnesium?

1 Answer
Jul 27, 2018

Answer:

What are the electronic configurations of the aluminum and magnesium atoms respectively?

Explanation:

For #Mg, Z=12, 1s^(2)2s^(2)2p^(6)3s^(2)#.

#Al, Z=13, 1s^(2)2s^(2)2p^(6)3s^(2)3p^1#.

And for the reaction....#M(g) + Delta rarr M^(+)(g) + e^(-)#

Now we assume that the valence electron is the electron that is ionized. A priori, would we not expect that a p-orbital electron would be more easily removed than a s-orbital electron, for the reason that the p orbital is FARTHER removed from the atomic nucleus, and has NO probability of occurring at the nuclear core.

But as chemists, as physical scientists, we should interrogate data...

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Does this table support our argument...?