Question

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

Answer 1

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.com

Are these data consistent with what we have argued?