Bonding, Structure and Properties of Matter
Map Your Gaps
Card 1 of 10
Swipe right if you know it, left if you don't
✔ Know
✖ Don't know
Ionic bonding
Metals lose outer electrons to form positive ions; non-metals gain electrons to form negative ions. The oppositely charged ions are held together by strong electrostatic attraction in a giant ionic lattice.
Sodium chloride is a giant lattice of Na+ and Cl− ions, not individual molecules.
Ionic bonding — Key Knowledge
- Ionic bond electrostatic attraction between oppositely charged ions
- Giant ionic lattice regular arrangement of ions
- Electron transfer metals lose, non-metals gain
Covalent bonding
Non-metal atoms share pairs of electrons so each atom achieves a stable electronic structure. Each shared pair of electrons is one covalent bond.
Hydrogen, water and oxygen are common examples of simple covalent molecules.
Covalent bonding — Key Knowledge
- Covalent bond shared pair of electrons between non-metals
- Single bond one shared pair
- Double bond two shared pairs
Metallic bonding
Metal atoms are arranged in a regular structure. The outer electrons are delocalised, forming a "sea" of free electrons surrounding positive metal ions.
This bonding model explains why metals conduct electricity and heat.
Metallic bonding — Key Knowledge
- Metallic bond electrostatic attraction between positive metal ions and delocalised electrons
- Delocalised electrons free to move through the structure
States of matter
Matter exists as solid, liquid or gas. Changes of state are physical changes — no new substances are formed and the process is reversible.
Particle arrangement and energy determine which state a substance is in.
States of matter — Key Knowledge
- Solid fixed shape, fixed volume
- Liquid takes shape of container, fixed volume
- Gas fills container, no fixed shape or volume
- Changes of state physical, reversible
Properties of ionic compounds
Ionic compounds have high melting and boiling points because of strong electrostatic forces throughout the lattice. They conduct electricity when molten or dissolved but not when solid.
It is the whole lattice that must be overcome, not individual bonds.
Properties of ionic compounds — Key Knowledge
- High melting point strong electrostatic forces, lots of energy needed
- Conduct when molten or dissolved ions free to move
- Do not conduct when solid ions fixed in lattice
Properties of small molecules
Small molecules have low melting and boiling points because the intermolecular forces between molecules are weak. The covalent bonds within molecules are strong but are not broken during changes of state.
When a molecular substance boils, it is the intermolecular forces that are overcome, not the covalent bonds.
Properties of small molecules — Key Knowledge
- Weak intermolecular forces little energy to overcome
- Low melting and boiling points, Do not conduct electricity no overall charge, no free electrons
Giant covalent structures
All atoms are linked by covalent bonds in a huge network. Very high melting points because many strong covalent bonds must be broken.
Diamond and graphite are both pure carbon — different properties come from different bonding arrangements.
Giant covalent structures — Key Knowledge
- Diamond each carbon bonded to four others, very hard, does not conduct
- Graphite layers of hexagons, layers slide, conducts electricity — delocalised electrons
- Silicon dioxide giant covalent, very high melting point
Metals and alloys
Metals conduct electricity and heat because delocalised electrons carry charge and energy. Layers of ions can slide over each other, making metals malleable.
Pure metals are often too soft for practical use, so alloys are used instead.
Metals and alloys — Key Knowledge
- Electrical and thermal conductivity delocalised electrons
- Malleable layers slide
- Alloys mixture of metals, different-sized atoms disrupt layers, harder than pure metals
Graphene and fullerenes
Graphene is a single layer of graphite — one atom thick, strong, light, and an excellent electrical conductor. Fullerenes are hollow carbon molecules with cage-like structures.
These carbon forms have specialised applications because of their unusual structures.
Graphene and fullerenes — Key Knowledge
- Graphene single layer of graphite, conducts electricity, very strong
- Fullerenes hollow carbon cages, e.g. C60 buckminsterfullerene
- Uses of fullerenes drug delivery, catalysis, lubricants
Nanoparticles
Nanoparticles are 1–100 nm in size, between individual atoms and bulk material. Their high surface area to volume ratio gives them different properties from the same material in bulk.
Smaller particles have a proportionally larger surface area, making them more reactive.
Nanoparticles — Key Knowledge
- Size range 1–100 nm
- High surface area to volume ratio, Uses catalysts, coatings, drug delivery, electronics, cosmetics
Map your gaps
Bonding, Structure and Properties of Matter
0%confident
✔
0
0
❓
0
0
✖
0
0