Bonding and Shapes Flashcards
metallic bonding
electrostatic force of attraction between a lattice of positively charged ions (cations), and free moving sea of delocalised electrons
metallic bonding properties
- good conductors of electricity when solid - good conductors of heat - malleable and ductile - high boiling point
Metalic bonding
good conductors of electricity when solid
Delocalised electrons flowing through the lattice which move and carry electrical charge
Metallic bonding
good conductors of heat
delocalised electrons flowing through the lattice which collide with metal atoms and pass on heat energy
Metallic bonding
malleable and ductile
Attraction between the metal lattice and delocalised electrons can take a fair amount of force/stretching before the lattice breaks and so it maintains properties whilst changing shape
Metallic bonding
high melting and boiling points
Attraction between the metal cations and delocalised electrons requires a lot of energy to overcome
ALLOYS
Combinations of two or more metals
- Harder than pure metals
- Less malleable than pure metals
- Poorer conductors than pure metals
Galvanisation
process of applying a protective zinc coating to steel or iron to prevent rusting
Ionic Bonding
3D ionic lattice held together by strong electrostatic forces of attraction between the oppositely charged ions eg. NaCl
Anion
- negative ions
- it has gained electrons
Cations
- positive ions
- loss of electrons
polyatomic ions
- acetate (ethanoate):
- nitrate:
- hydroxide:
- permanganate:
- cyanide:
- sulfate:
- carbonate:
- chromate:
- dichromate:
- phosphate:
- ammonium:
- hydrogen carbonate:
- acetate (ethanoate): CH₃COO⁻
- nitrate: NO₃⁻
- hydroxide: OH⁻
- permanganate: MnO4⁻
- cyanide: CN⁻
- sulfate: SO₄⁻²
- carbonate: CO₃⁻²
- chromate: CrO₄⁻²
- dichromate: Cr2O7⁻²
- phosphate: PO₄³⁻
- ammonium: NH₄⁺
- hydrogen carbonate: HCO₃⁻
covalent bonding
- electrostatic force of attraction between the nuclei of two atoms in a shared pair (or pairs) of electrons between them
Dative covalent bond
Covalent bond of the shared electrons are contributed by one atom only
shape of molecule
- 2 bonding pairs, no lone pairs : linear
- 3 bonding pairs, no lone pairs : trigonal planar
- 4 boding pairs, no lone pairs : tetrahedral
- 3 bonding pairs, 1 lone pairs : trigonal pyramida;
- 2 bonding pairs, 2 lone pairs : V shaped/ bent
- 1 bonding pair, 3 lone pairs : linear
- VESPER theory treats double and triple bonds as if they were single bond or
lone pairs
types of giant covalent molecules
(1) Giant Covalent Molecules
(2) covalent layer structures
covalent network structures
- insoluble in water
- high melting and boiling point
- do not conduct electricity or heat
- very hard
- e.g. diamond silicon dioxide SiO2
covalent layer structures
- insoluble in water
- high melting and boiling point
- good conductors of heat :
• spare electron becomes delocalised between the layers. these mobile
electrons enable graphite to conduct electricity - soft :
• graphite layers can slide over one another making it soft and slippery
(dispersion forces between layers)
intermolecular bonding
(1) dispersion
(2) dipole - dipole
(3) hydrogen
dispersion
- occur between all molecule ( polar/ non polar)
- very weak
- bigger the molecule, stronger the dispersion force between molecules when
a change of state is required because there is a greater surface area for them
to act across - instantaneous- induced dipole : electrons are constantly moving. at one
instant there will be more electron at one of the molecule that the other. this
is called temporary dipole.
dipole-dipole
- between polar molecules
- a dipole arises when there is a difference between electronegativity between
2 atoms in a molecule
hydrogen
- H bonded to N, O, F
