Zusammenfassung der Ressource
GCSE AQA Chemistry 2 Bonding
- Atoms
- Mass no. -> total no. of
protons and neutrons
- Electrons not counted because
their mass is negligible
- Atomic no. -> no. of protons
- Compounds
- Atoms of two or more elements
are chemically combined
- Isotopes
- Different atomic forms of the same
element which have the same no. of
protons but a different no. of neutrons
- Same atomic no. but
different mass no.
- Ionic Bonding
- Atoms gain/lose electrons to
form charged particles (ions)
- Strongly attracted
to each other
- Shells with 1/2 outer electrons want
to get rid so left with full shells
- Metals lose to form positive ions
- Nearly full shells want to gain to get full shell
- Non-metals gain to
form negative ions
- Ionic compounds
- Giant regular ionic
lattice structure
- Strong electrostatic forces
of attraction between
oppositely charged ions
- Properties - high melting & boiling
points, will carry electric current when
molten & dissolve easily in water
- Covalent Bonding
- Sharing electrons
- In their outer shells
- Both atoms feel like they have a full outer shell
- Non-metals only
- Covalent substances
- Simple Molecular
- Atoms form strong CBs to form small molecules
- Intermolecular
forces - v. weak
- Melting & boiling points v.
low - bonds easily broken
- Most are gases/liquids
at rm. temp.
- Don't conduct electricity
- Giant Covalent Structures
(Macromolecules)
- All atoms bonded to each
other by strong CBs
- V. high melting/boiling points
- Don't conduct electricity
- Examples:
- Diamond
- Forms 4 CBs
- Hardest natural substance
- Graphite
- Forms 3 CBs
- Creates layers - free to slide
- Weak intermolecular
forces between layers
- Only non-metal - good conductor of heat/electricity
- Each atom has one delocalised electron
- Silicon dioxide (Silica)
- Giant structure of silicon & oxygen
- Metallic Structures
- Giant structure
- Delocalised electrons - come from
outer shell of every metal atom
- Free to move -
good conductors
of heat/electricity
- Hold atoms in regular structure
- Strong forces of electrostatic attraction between
positive metal ions & negative electrons
- Layers of atoms can slide -
metals can be bent/shaped
- Alloys
- Mixture of 2 or more metals
- Different elements have
different sized atoms
- Layers distorted - hard to
slide so alloys are harder