Atomic Radius & Ionization Energy

As you go down the periodic table, atoms get bigger because…

• They have more energy levels

• They have more neutrons

As you go across the table (left → right), atoms get smaller because…

• They have more protons pulling the electrons in

• They have fewer electrons

Which atom is bigger?

• Kr

• Rn

Which statement is correct?

• Atomic radius gets smaller across → and bigger down ↓

• Atomic radius gets bigger across → and smaller down ↓

Put these from smallest → largest atomic radius: (Be, Ca, Rb, Ra)

• Be → Ca → Rb → Ra

• Ra → Rb → Ca → Be

More protons means…

• Stronger pull on electrons

• Weaker pull on electrons

Which atom is the largest?

• Nitrogen (N)

• Lithium (Li)

Ionization energy means…

• Energy needed to remove an electron

• Energy needed to add an electron

Which is smaller: indium or gallium?

• Gallium

• Indium

Which shows ionization energy from low → high?

• Cl → S → P → Al

• Al → P → S → Cl