Topics 2 & 3 - Atomic Structure & Periodicity

Define 1st ionization energy. + standard

The energy required to remove one electron from a gaseous atom. Standard means its at STP.

Define 2nd ionization energy.

The energy required to remove one electron from a monopositive gaseous atom.

Define 1st and 2nd ionization energy.

The energy required to remove two electrons from a gaseous atom.

Define 1st electron affiinity.

Energy change when an electron is added to a gaseous atom.

Define electronegativity.

Ability of an atom to attract a pair of bonded electrons.

Define atomic radii.

Half the inernuclear distance, half the distance between two bonded atom’s nuclei.

Why does the atomic radii decrease across periods?

• The electrostatic attraction beween protons and electrons increases as atomic # increases.

• Electrons are added to the same shell

Reactivity increases or decreases down the alkali metals and the halogens?

• Increase down the alkali metals

• Decrease down the halogens

Name both of the f-block periods.

• Lanthanides

• Actinides