Transcript Periodic Trends

Periodic Trends
The physical and chemical properties
of the elements are periodic functions
of their atomic numbers.
Atomic Radius

Distance between the radii of two atoms
Trends in the periodic table:
Atomic radius

Radius DECREASES as you go left to right
across a period.
Going across the period
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Electrostatic attraction increases.
Electrons are pulled closer to the nucleus.
Valence electrons are more tightly held.
Trends in the periodic table:
Atomic radius

Radius INCREASES as you down a group.
Going down a group
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Orbitals are larger.
Electrons are farther from the nucleus.
Valence electrons are less tightly bound.
Ionization Energy

Amount of energy required to remove an
electron from the ground state of a gaseous
atom or ion.
First ionization energy is that energy required to
remove the first electron.
 Second ionization energy is that energy required to
remove the second electron, etc.
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Ionization Energy
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It requires more energy to remove each successive
electron.
When all valence electrons have been removed, the
ionization energy takes a quantum leap.
Trends in First Ionization
Energies

As one goes down a
column, less energy is
required to remove the
first electron.
Trends in First Ionization
Energies
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Generally, as one goes
across a row, it gets
harder to remove an
electron.
Electronegativity
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The tendency of an atom to attract electrons to itself
when combined with another element.
It increases going left to right across a period.
It decreases going down a group.
Electronegativity