CH. 8 | Atoms and Periodic Properties

Electron’s charge-to-mass ratio

Atomic Number

• # of protons in the nucleus

• Elements distinguished by atomic #

• # of protons = # of electrons in neutral atoms

Isotopes

Same # of protons and electrons, different # of neutrons

Nuclear Notation

Periodic Table Notation

Mass Number

Number of protons + neutrons

Atomic Mass Unit

1/12 of carbon - 12 isotope mass

Atomic Weight

Atomic mass of an element, averaged over naturally occurring isotopes

Quantum Mechanics

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Electron Configuration

Arrangement of electrons into atomic orbitals

• When writing them, electrons fill available orbitals in order of increasing energy

Picture

Periodic Table (Understand / Take info from it)

• Periodic Chemical Properties
  → Rows = Periods
  ↓ Columns = Families or Groups

• Electrons in outer orbits determine chemical properties

• Valence electrons = Roman Numerals

• Alkali metals (IA)

• Alkaline earths (IIA)

• Halogens (VIIA)

• Noble gases (VIIIA)

Metals, Nonmetals, Semiconductors