Periodic TrendsPeriodic Trends

The physical and chemical The physical and chemical properties of the elements properties of the elements

are periodic functions of their are periodic functions of their atomic numbers.atomic numbers.

Atomic RadiusAtomic Radius

Distance between the radii of two Distance between the radii of two atomsatoms

Trends in the periodic Trends in the periodic table: Atomic radiustable: Atomic radius

Radius DECREASES as you go left to Radius DECREASES as you go left to right across a period.right across a period.

Going across the periodGoing across the period

Electrostatic attraction increases.Electrostatic attraction increases. Electrons are pulled closer to the nucleus.Electrons are pulled closer to the nucleus. Valence electrons are more tightly held.Valence electrons are more tightly held.

Trends in the periodic Trends in the periodic table: Atomic radiustable: Atomic radius

Radius INCREASES as you down a Radius INCREASES as you down a group.group.

Going down a groupGoing down a group

Orbitals are larger.Orbitals are larger. Electrons are farther from the nucleus.Electrons are farther from the nucleus. Valence electrons are less tightly bound.Valence electrons are less tightly bound.

Ionization EnergyIonization Energy Amount of energy required to Amount of energy required to

remove an electron from the ground remove an electron from the ground state of a gaseous atom or ion.state of a gaseous atom or ion. First ionization energy is that energy First ionization energy is that energy

required to remove the first electron.required to remove the first electron. Second ionization energy is that energy Second ionization energy is that energy

required to remove the second electron, required to remove the second electron, etc.etc.

Ionization EnergyIonization Energy

It requires more energy to remove each It requires more energy to remove each successive electron.successive electron.

When all valence electrons have been When all valence electrons have been removed, the ionization energy takes a removed, the ionization energy takes a quantum leap.quantum leap.

Trends in First Trends in First Ionization EnergiesIonization Energies

As one goes down As one goes down a column, less a column, less energy is required energy is required to remove the first to remove the first electron.electron.

Trends in First Trends in First Ionization EnergiesIonization Energies

Generally, as one Generally, as one goes across a goes across a row, it gets row, it gets harder to remove harder to remove an electron.an electron.

ElectronegativityElectronegativity The tendency of an atom to attract electrons to The tendency of an atom to attract electrons to

itself when combined with another element.itself when combined with another element. It increases going left to right across a period.It increases going left to right across a period. It decreases going down a group.It decreases going down a group.

ElectronegativityElectronegativity