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.