Download Atomic Size

Atomic Size
The atomic radius increases
from top to bottom in a group in
the periodic table.
As you move down a group in
the periodic table, atomic size
generally increases.
• WHY?
The atomic radius decreases
from left to right across a period
in the periodic table.
• WHY?
• The apparent discontinuities in this diagram reflect the
difficulty of comparing the radii of atoms of metallic and
nonmetallic bonding types. Radii of the noble gas
elements are estimates from those of nearby elements.
• Lithium has the largest atomic radius in
the second period.
• As the number of electrons added to
the same energy level increases,
atomic size generally decreases.
• List the symbols for sodium, sulfur, and
cesium in order of increasing atomic
radii _____________________
• Sulfur, Sodium, Cesium
• The largest atom in Group 1A is _____
• Fr
• The smallest atom in Group 7A is _____
• F
Ions and Ionization
• Ions form when electrons enter or leave
atoms.
• The charge of a cation is positive.
Cations are smaller than the original
atom.
• An anion has a negative charge. Anions
are larger than the original atom.
• Removing one electron from an atom
results in the formation of an ion with a
1+ charge.
• Adding one electron to an atom results
in the formation of an ion with a 1charge.
• Ionization energy - energy required to
move an electron out of an atom
• Ionization energy decreases from top to
bottom and increases from left to right
on the periodic table.
Among Na, K, and Cs, which
element has the lowest
ionization energy?
• Cesium (Cs)
Which is larger, K or K+?
• K
Which is smaller, Li, Li+, F, or F?
• Li+