Periodic Trends

Atomic Radius

Defined as half the distance between the nuclei of two atoms Going across the periodic table ◦ But why are they smaller towards the right?

Electron Shielding Shielding electrons _____________________________ They “shield” the valence electrons from the _______________from the nucleus As you add electrons across a period, they are added to the SAME energy level, ______________________________ The increased nuclear charge is able to _______________________________ _______________________________

Atomic Radius Going down a group

Ionic Radius Ion – Atoms lose electrons to become Atoms gain electrons to become

Ionic Radius Positive ions ◦ Always become __________ ◦ The lost electron(s) is the valence level ________________ ________________ Negative ions ◦ Always become ______________ ◦ Addition of electrons increases repulsion.

Ionic Radius

Ionization Energy

The energy required to remove an electron from an atom

Ionization Energy Increases across the periodic table Decreases as you go down the periodic table

Ionization Energies

Electronegativity

Electronegativity The ability of an atom to attract an electron from another atom. On a scale from.79 to 3.98 Pauling’s

Electronegativity Increases across the periodic table Decreases as you go down the periodic table