Electrons and bonding

Electrons and bonding

1. Orbitals

   • 'S'
     • Shape of a sphere
     • Can hold 1 or 2 electrons
     • Greater the shell number greater radius of orbital.
   • 'P'
     • Electron cloud shape of dumb-bell.
     • Each can hold 1 or 2 electrons
     • Three separate p orbitals at right angles to each other.
     • Greater shell number further away orbital is from nucleus.
     • each shell from n=2 contains 3 p-orbitals
   • 'D' and 'F'
     • each shell from n=3 contains 5 d orbitals
     • each shell from n=4 contains 7 f orbitals
   • Sub-shells
     • orbitals of same type are grouped together as sub shells

2. Ionic bonding

   • Common cations and anions
     • Cations
       • Metal ions IE NA+ and ammonium ions
     • Anions
       • Non metal ions and polyatomic ions
   • Giant ionic lattice
     • Contains billions and billions of ions.
     • Key structural feature of ionic compounds
   • Properties due to structure
     • Melting and boiling pts
       • MELTING AND BOILING PTS: High due to large amount of energy needed to over come strong electrostatic attraction
     • Solubility
       • most dissolve in polar solvents i.e. water, water breaks down the lattice that surrounds each ion in solution, but some compounds are too big. depends on the relative strengths of attractions within lattice
       • 2 main processes: 1. lattice must be broken down.
         • 2. water molecules must attract nd surround the ions
     • Electrical conductivity
       • In a solid state: DOES NOT CONDUCT. due to ions in fixed shape so there are no mobile carriers charge.
       • When in liquid or dissolved in water: solid lattice breaks down so ions free to move as mobile charge carriers.
   • Dot and cross - giving of electrons

3. Covalent bonding.

   • Orbital overlap
   • Single covalent
     • LONE PAIRS: are paired electrons that are not shared. Can also be added to displayed formulae as two dots.
     • HYRDROGEN: 1 BOND, OXYGEN 2 BONDS, NIRTOGEN 3, CARBON 4 BONDS FORM
   • Double covalent bonds
     • the electrostatic attraction is between the two shared pairs of electrons and the nuclei of the bonding atoms.
     • All atoms have 8 electrons in their outer shell

Images and files in the map