Periodic TrendsPeriodic Trends

Atomic RadiusAtomic Radius

Atomic RadiusAtomic RadiusDefined as half the distance

between the nuclei of two atomsGoing across the periodic table

◦But why are they smaller towards the right?

Electron ShieldingElectron ShieldingShielding 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 RadiusAtomic RadiusGoing down a group

Ionic RadiusIonic RadiusIon – Atoms lose electrons to become

Atoms gain electrons to become

Ionic RadiusIonic RadiusPositive ions

◦ Always become __________

◦ The lost electron(s) is the valence level ________________________________

Negative ions◦ Always become

______________◦ Addition of

electrons increases repulsion.

Ionic RadiusIonic Radius

Ionic RadiusIonic Radius

Ionization EnergyIonization Energy

Ionization EnergyIonization EnergyThe energy required to remove

an electron from an atom

Ionization EnergyIonization EnergyIncreases across

the periodic table

Decreases as you go down the periodic table

Ionization EnergiesIonization Energies

ElectronegativityElectronegativity

ElectronegativityElectronegativityThe ability of an atom to attract

an electron from another atom.On a scale from .79 to 3.98

Pauling’s

ElectronegativityElectronegativityIncreases across

the periodic table

Decreases as you go down the periodic table