# Electron Affinity/Ionization Energy

## Homework Statement

(c) the ionization energy of Cl-
_________kJ/mol

(e) the electron affinity of Cl+
_________kJ/mol

Ionization Energy Chart

I(sub1) I(sub2) I(sub3) I(sub4) I(sub5)

Cl 1255 2295 3850 5160 6560

## The Attempt at a Solution

At first when I saw the Cl-, I thought maybe they added an extra electron to become Ar and I used the Ionization Energy (I sub1) for Ar but it wasn't right...

I was wondering if there are any difference between getting the Ionization Energy of Cl+ and Cl? I mean the book gave me the chart of I (sub1) to I (sub7) of Cl but nothing about the ions of Cl. Is there an equation or anyway where you could figure out the energy? (same question regarding electron affinity)

P.S.
Yay! First post!!

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Gokul43201
Staff Emeritus
Gold Member

## The Attempt at a Solution

At first when I saw the Cl-, I thought maybe they added an extra electron to become Ar and I used the Ionization Energy (I sub1) for Ar but it wasn't right...
To change from one element to another, you need to actually change the number of protons in the nucleus. Just moving around electrons will not achieve this.

I was wondering if there are any difference between getting the Ionization Energy of Cl+ and Cl?
Yes, there is.

I mean the book gave me the chart of I (sub1) to I (sub7) of Cl but nothing about the ions of Cl.
You need to go back to the definitions. How is the second ionization energy, I2(Cl) defined? The answer is right there in that definition.

Is there an equation or anyway where you could figure out the energy? (same question regarding electron affinity)