F321: Bonding and Structure

F321: Bonding and Structure

1. Ionisation Energies

   • Factors affecting ionisation energies
     • Atomic radius: the greater the radius, the smaller the nuclear attraction by the outer electrons
     • The greater the nuclear charge, the greater the attraction on the outer electrons,
     • Electron shielding: inner electrons repel outer electrons, this is called shielding, the more inner shells there are, the greater the shielding and the smallerthe nuclear attraction experienced by the outer electrons.
   • Successive ionisation energies
     • successive ionisation energies are the measure of energy required to remove each electron in turn
     • e.g second ionisation energy is how easily a 1+ ion can turn into a 2+ ion by loosing 11electron
     • each successive ionisation energy is higher than the one before
       • as each electron is removed there is less repulsion between the electrons and each shell with de drawn in closer to the neucleus
       • As the distance from the electron to the nucleus is less the higher the nuclear attraction therefore a higher ionisation needed to loose another electron

2. Shells and orbitals

   • electrons in each shell
     • n=1 shell=1 electrons =2
     • n=2 shell=2 electrons =8
     • n=3 shell=3 electrons =18
     • n=4shell =4 electrons =32
     • each shell holds up to 2n^2
     • principal quantum number = n
   • Atomic Orbitals
     • S-orbitals
       • sphere shape
       • In every shell
       • Holds up to 2 electrons
     • P-orbitals
       • 3D dumbbell shape
       • from the second shell up they contain 3 p orbitals at right angles to each other
       • each p orbital can hold 2 electrons, total p electrons =6
     • D&F-orbitals
       • from shell 3 they contain 5 d orbitals and total of 10d electrons
       • from shell 4 they contain 7 f orbitals and total of 14f electrons

3. Sub-shells and energy levels