1. Periodic Trends Continued
Atomic Radius
Ionization Energy
Ionic Size
Electronegativity

2. Trend: Atomic Radius
Atomic Radius is: ½ the distance between nuclei of 2 atoms of the same element.
Trend
Reasoning: Increased nuclear charge pulls e- closer
More principal energy levels = Bigger atom

3. Atomic Radii for Selected Atoms

4. Trend: Ionization Energy
Ions: are atoms that have gained or lost electrons.
Ionization Energy is: The energy required to remove an electron from a neutral atom at ground state.
Trend
Reasoning: Increased nuclear charge pulls e- closer so they are
harder to lose.
As the atom gets bigger the nucleus has less effect on
the e-in the highest shells.

5. Trend: Ionic Size
Metals tend to lose electrons to nonmetals that tend to gain electrons.
Cations are + ions (metals)
Anions are – ions (nonmetals)
Trend
Reasoning: Increased nuclear charge pulls e- closer so they are
harder to lose.
More principal energy levels = Larger

6. Trend: Electronegativity
Ability of an atom to attract electrons from other atoms (Electron Greediness)
Trend *Excludes Noble gases
Reasoning: Metals tend to lose e-
Nonmetals tend to gain e-
The atoms are bigger and the nucleus has little
attraction for extra electrons.