Isotope

Same element with a different mass

Ion

Atoms or molecules with an electrical charge

Cations

Positively charged atoms/molecules

Anions

Negatively charged atoms/molecules

amu

Atomic mass unit

Atomic number

Number of protons

Mass number

Protons + neutrons (amu unit)

Nuclide

The nucleus of an atom

Alpha particles

Helium nuclei

Mass of 4 amu

Charge of +2

Ionic compounds (cpds)

Metals attached to nonmetals

Known as formula units

NOT TRUE MOLECULES

Molecular Cpds (or Covalent)

Nonmetals attached to other nonmetals

TRUE MOLECULES

Diatomic elements

The 7 diatomic elements are also true molecules.

Periodic table

• The rows are called periods

• The columns are called families or groups

Metals

• Conduct electricity and heat

• Malleable

• Ductile

• Very reactive and unstable

• Silver/grey solids (Exceptions Au/Cu)

Nonmetals

• Insulators (don’t conduct heat or electricity)

• Brittle solids

• Some gases

• Not very malleable or ductile

Metalloids

• Found along the staircase

• Don’t fit neatly into the metal or nonmetal category.

• Contain some characteristics of each group.

True metals

• Alkali family (First column)

• Alkaline Earth family (Second column)

Nonmetals

• Noble gases (He family)

• Halogens (F family)

• Chalcogens (O family)

Transitional metals

• Most create very colorful cpds

• All are silver or grey solids except Hg (silver liquid), gold (yellow solid) and copper (brown solid).

• These have all of the characteristics of true metals but to a lesser degree.