Trends in Atomic Radius and Ionization Energy

Atomic radius trend down a group

Increases (atoms get bigger)

Atomic radius trend across a period

Decreases (atoms get smaller)

Ionization energy trend down a group

Decreases (easier to remove electrons)

Ionization energy trend across a period

Increases (harder to remove electrons)

Effective nuclear charge (Z_eff) across a period

Increases (more protons pulling electrons)

Effective nuclear charge down a group

Decreases (shielding increases)

Which has the largest atomic radius?

Rb

Which has the highest ionization energy?

Argon (Ar)

Bond between metal and nonmetal

Ionic bond

Bond between two nonmetals

Covalent bond

What is lattice energy?

Energy to separate one mole of an ionic solid into gas-phase ions

Factors that increase lattice energy

Smaller ions and higher charges

Which has greater lattice energy: MgCl₂ or KCl?

MgCl₂

Example of ionic compound

NaCl

Example of covalent compound

CO₂

Definition of atomic radius

Distance from nucleus to outermost electron

Definition of ionization energy

Energy needed to remove an electron

Definition of lattice energy

Energy required to break apart an ionic solid