By: Katie, Steph, Jen, & Tyler

Ionization Energy - the minimum energy required to remove an electron from the ground state of an isolated gaseous atom or ion

Ionization is always an endothermic process:

it requires energy to remove an e- from an atom or ion

1st Ionization Energy

2nd Ionization Energy

Energy needed to remove 1st electron

(neutral atom)

Energy needed toremove 2nd electron

… And so on with I3, I4, etc…

Ionization energy as successive electrons are removed

WHY? Ion becomes more+

Opposite to those for atomic and ionic radii

Generally, smaller atoms or ions have higher ionization energies

A smaller atom means...More attraction between electrons and protons

So… it takes more energy to pull away the e-

Alkali metals: lowest ionization energies of the atoms in each row

Noble gases:highest ionization energies of the atoms in each row

Ionization energy increases as you go across a row

Ionization energy decreases for atoms as you go down a column

In general:

Remember Yo Periodic Trends Homie; G-unit

Electrons removed first: Have orbitals with largest principal

quantum number (n)

2 electrons removed from Fe: [Ar] 4s 3d⁶ Fe [Ar] 3d⁶

Example:

2 2+

Go practice those trends!