Bondings Flashcards
Ionic Bonding
? The electrostatic attraction between oppositely charged ions
Metallic Bonding
? Electrostatic attraction between delocalised electrons and positively charged metal ions
Covalent bonding
? Strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
Dative Covalent bond
? One atom donates both of the electrons in the covalent bond. They are equivalent to other covalent bonds.
Electronegativity
? The power of an atom to attract a pair of electrons in a covalent bond.
? The measure of the attraction of a bonded atom for the pair of electrons in the covalent bond.
Non polar covalent bonds
? Forms when the atoms (made of the same element) have identical electronegativities
Polar covalent bonds
? Forms when the elements in the bond have different electronegativities (of around 0.3-1.7)
Intramolecular forces
? forces within molecules
Intermolecular forces
? forces between molecules
Hydrogen bonding
? Occurs between a hydrogen atom and a lone pair of electrons on a very electronegative atom. (H-O, H-N, H-F)
Melting point
? Is the temperature a species starts to melt which the same temperature the species starts to freeze
Boiling point
? Is the temperature a species starts to boil which is the same temperature the species starts to condense
Valence Shell electron pair repulsion theory (VSEPR)
? The shape adopted by a single molecule or ion is that which keeps repulsive force to a minimum.
electrons in the outer shell of atoms arrange themselves as far apart as possible to minimise repulsion
decrease by 2.5 degrees
The shape of: 2 electron pairs - both bonding pairs
Linear, 180 degrees
The shape and angle of 3 electron pairs - 3 bonding pairs
Trigonal planar 120 degrees
The shape and angle of 3 electron pairs - 2 bonding pairs & 1 lone pair
Bent, around 119 degrees
Order of strengths of repulsion
Lone-lone > Lone-bonding > bonding-bonding
4 electron pair; 4 bonding pairs
Tetrahedral, 109.5 degrees