Chapter 5

• Orbital


  A region where you can have up to 2 electrons, with opposite spin

  
• Orbitals


  • Each type of orbitals have different shape
• Shells


  • For a level we use n = 1, n = 2, n = 3
  • Regarded as energy levels
  • Energy increases as shell number increases
  • The energy number is called quantum number n

  
• 1. orbital


  • Within a shape of sphere - hold up to 2 electrons
  • The greater the shell number the greater the radius of s-orbital

  
• 1. orbital


  • Electron cloud is within the shape of a dumbbell
  • There are 3 separate orbitals each can contain 1-2 electrons
  • At different angles are called px, py, & pz
  • Start from n=2

  
• D & f-orbital


  • More complex
  • D from n=3 and f from n=5
  • D has 5 separate clouds each can hold 1-2 electrons
  • F has 7 separate clouds
• Sub-shell


  Orbitals of the same type are called sub-shells
• Filling orbitals


  Electronic configuration
• Isoelectronic


  Same electron configuration, same number of shells
• Si = [Ne] 3s2 3p2
• Na = [Ne] 2s2 2p6 3s1
• Ne = [He] 2s2 2p6
• Na = [Ne] 3s1
• Cl = [Ne] 3s2 3p5
• K = [Ar] 4s1
• Br = [Ar] 3d10 4s2 4p5
• Ga = [Ar] 3d10 4s2 4p1
• Fe = [Ar] 3d6 4s2
• Ar = [Ne] 3s2 3p6
• Cr = [Ar] 3d5 4s1
• Mn = [Ar] 3d5 4s2
• Cu = [Ar] 3d10 4s1
• Li = [He] 2s1
• S2- = [Ne] 3s2 3p6
• Ca = [Ar] 4s2
• Sc = [Ar] 3d1 4s2
• Sc3+ = [Ar]
• Co = [Ar] 3d7 4s2
• Co2+ = [Ar] 3d7
• Ionic compounds / bonds

  Electrostatic attraction between oppositely charged ions
• Charges


  • Group 1 is +1
  • Group 2 is +2
  • Group 3 is +3
  • Group 5 is -3
  • Group 6 is -2
  • Group 7 is -1
• Polyatomic


  Two or more bonded atoms in an ionic bonding
• Giant ionic lattice


  • 3D structure of oppositely charged ions, held together by strong ionic bonds
  • High melting and boiling points due to strong electrostatic force between opposite charges
  • Need high energy to break the bonds
• Solubility


  Dissolved in polar solvent (water), but the one with stronger electrostatic force between oppositely charged ions wouldn't dissolve
• Electrical conductivity of ionic compounds


  • Solid - no electron or ions to carry the charge
  • Liquid or aqueous - ionic lattice breaks down, ions free to move as mobile charge carriers
• The strong electrostatic attraction between the oppositely charged ions need a high energy in order to break the strong electrostatic attraction which makes these ionic compounds have a high melting and boiling points
• It's difficult to dissolve ionic compounds in polar solvent like water because the hydrogen bond to the negative ions whereas the oxygen bond to negative ions which breaks the ionic compound
• Covalent bonding


  Strong electrostatic attraction between shared pair of electrons and the nucleus of the bonded atoms
• Covalent compounds and molecules


  • Occur with non-metallic elements, compounds of non-metallic elements, and polyatomic ions
• Covalent bond


  • Overlapping of atomic orbitals each containing 1 electron, to give a shared pair of electrons
  • The shared pair is attracted to both atoms' nucleus
  • The attraction is localised - acting only on shared pair of electrons and nucleus of the atoms