5.1

• How many electrons can shell 2 hold?

  8 electrons
• How many electrons can shell 3 hold?

  18 electrons
• How many electrons can shell 4 hold?

  32 electrons
• What is the formula for finding out the maximum number of electrons that a shell (n) can hold?

  2n^2
• What is a shell?

  An energy level where electrons can be found.
• What is an atomic orbital?

  A region around the nucleus that can hold up to two electrons with opposite spins.
• How are electrons modelled?

  As a negatively-charged cloud with the shape of an orbital.
• What are the 4 orbitals?

  s, p, d, f.
• What shape is an s-orbital?

  Spherical.
• What shape is an p-orbital?

  Dumb-bell.
• How many p-orbitals will shell 2 have?

  3 orbitals (6 electrons maximum).
• How many d-orbitals will shell 3 have?

  5 orbitals (10 electrons maximum).
• How many f-orbitals will shell 4 have?

  7 orbitals (14 electrons maximum).
• What does each new shell gain?

  A new type of orbital.
• What is the maximum amount of electrons a single orbital can hold?

  2 electrons.
• Which sub-shell fills first: 3d or 4s?

  4s.
• How do electrons act towards each other?

  They repel.
• How do electrons counteract repulsion?

  By having opposite spins to one another.
• How do electrons fill orbitals?

  One electron occupies each orbital before pairing can begin.
• How should electron configuration be written?

  In shell order rather than order of filling.
• Which group can be used to shorten electron configurations?

  Noble gases.
• How do d-block elements empty their shells to become ions?

  The 4s sub-shell empties before the 3d sub-shell.