Metals

Common characteristics:

• Metallic luster (shine)
• Generally solids at room temperature
• Malleable
• Ductile
• Conduct heat and electricity
• Exist as extended planes of atoms
• Combine with other metals to form alloys which have metallic characteristics
• Form positive ions, e.g.  Na⁺, Mg²⁺, and Al³⁺

Nonmetals

Common characteristics:

• Rarely have metallic luster (shine)
• Generally gases at room temperature
• Neither malleable nor ductile
• Poor conductors of heat and electricity
• Usually exist as molecules in thier elemental form
• Combine with other nonmetals to form covalent
• Generally form negative ions, e.g.  Cl^-, SO₄^2-, and N^3-

The differences in the characteristics of metals and nonmetals can be explained by the following:

1. Metals have relatively few electrons in their valence shells.
2. Metals have lower ionization energies than nonmetals.
3. Metals have smaller electron affinities than nonmetals.
4. Metals have larger atoms than nonmetals.

1) As you move across a period, metallic character decreases and nonmetallic character increases.

2) As you move down a group, metallic character increases and nonmetallic character decreases.

Semimetals (Metalloids)

• A class of 8 elements that have properties of both metals and nonmetals.

Common characteristics:

• Generally look metallic but are brittle (not malleable or ductile)
• Neither good conductors or insulators; instead they are semiconductors.

Next:  "Intramolecular Forces of Attraction"