Electron structure Flashcards Preview

CHEM - 2.2.1 Electrons and Bonding + Ionic and Covalent > Electron structure > Flashcards

Flashcards in Electron structure Deck (5)
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1
Q

What are shells?

A
  • Shells are regarded as energy levels.
  • Energy increases as shell number increases.
  • Shell number or energy level number is called the PRINCIPLE QUANTUM NUMBER ‘n’.
2
Q

Atomic orbitals

A
  • Shells are made up of atomic orbitals.
  • An atomic orbital is a region around the nucleus that can hold up to two electrons, with opposite spins.
  • There are diff. types of orbitals: s-,p-,d- and f-
  • Each has diff. shape.
  • Models show orbitals as a region in space where there is high probability of finding an electron.
3
Q

Types of sub-shells

A

s-orbital:

  • Sphere shape
  • No. of orbitals: 1
  • Max no. of electrons: 2

p-orbital:

  • Dumb-bell shape
  • No. of orbitals: 3
  • Max no. of electrons: 6

d-orbital:

  • No. of orbitals: 5
  • Max no. of electrons: 10

f-orbitals:

  • No. of orbitals: 7
  • Max no. of electrons: 14
4
Q

Rules for how orbitals are occupied by electrons

A
  • Orbitals fill in order of increasing energy.
  • Electrons pair with opposite spins:
    > Electrons can spin up or down and arrows show these.
    > 2 electrons in an orbital must have opp. spins.
    > Opposite spins counteract repulsion between the neg charges.
  • Orbitals with the same energy (e.g p- or s-) are occupied singly firs before pairing:
    > Orbitals can’t be left empty.
5
Q

Electron configuration

A
  • 4s sub shell FILLS before 3d sub shell.

- 4s sub shell also EMPTIES before 3d.