Distinguish between the first, second and third ionization energies of an atom?

1 Answer
Jan 31, 2018

Well, by definition, "the first ionization energy...."

Explanation:

Well, by definition, "the first ionization energy" is the energy associated with the formation of one mole of gaseous cations, and electrons, from one mole of gaseous atoms....i.e.

M_"some atom"(g)+Delta_1rarrM^(+)(g)+e^(-)

And Delta_1="1st ionization energy...."

And the "second ionization energy" is the is the energy associated with the formation of one mole of gaseous dications, and electrons, from one mole of gaseous cations....i.e.

M^(+)(g)+Delta_2rarrM^(2+)(g)+e^(-)

And Delta_2="2nd ionization energy...."

And Delta_3="third ionization energy...."

M^(2+)(g)+Delta_3rarrM^(3+)(g)+e^(-)

From first principles, we would expect that Delta_3>Delta_2>Delta_1....why?

Well, for a start, the successive ionization energies remove an electron from an atom that is ALREADY positively charged. And, the electron may be a non-valence electron, i.e. it may be from an inner non-valence shell, for which more energy is required to remove this electron.

But a scientist interrogates data....

thomsonscience.wrodpress.comthomsonscience.wrodpress.com

Are these data consistent with what we have argued?