C3 Structure and bonding

C3.2 States of matter
1. Elements form compounds when reacting by gaining or losing electrons, or by sharing electrons.
2. Non metallic elements joining together are covalent bonds.
3. Metallic and non metallic elements form and produce omicron compounds.
  1. The metal loses the electron forming + ions.
  2. Non metals gain electrons to form - ions.
4. Oppositely charged ions attract each other in the ionic compound, ionic bonding.
5. Ionic bonding lets two elements have a a complete structure forming a Nobel gas.
C3.1 States of matter
1. Particle theory describes the movement and arrangement of particles.
2. Solids are packed closely together in a fixed arrangement. They vibrate constantly.
3. Liquids are close together in a changing random arrangement, they move around.
4. Gases are much further apart in a random arrangement, they move very quickly.
5. Solids turn to liquids at melting point, temperature increases so the particles vibrate more and faster.
  1. At the melting point there is enough energy to break the forces between between particles. They break away from there fixed position and start to move, a liquid is formed.
6. Liquid turns to gas at boiling point. Temperature increases and some of the particles can escape from the surface area of the liquid before boiling point is reached. The liquid evaporates. Bubbles of liquid rise to the surface freely and a gas is formed.
7. Substances with higher melting and boiling points have stronger inter molecular forces between their particles.
8. Each state is reversible, gases condense to form liquids, liquids freeze to form solids.
C3.3 Ionic bonding
1. Formed when metals react with non metals.
2. Held together by strong intermolecular forces of attraction which act in all directions.
3. Giant structures are formed.
  1. Could also be a giant lattice.
C3.4 Giant ionic structures
1. Giant structures in which many strong electrostatic forces operate, in all directions.
2. It takes a lot of energy to overcome the ionic bonds to melt the solid.
  1. Therefor ionic compounds have high melting and boiling points.
3. When melted there ions are free to move, so they can conduct electricity in liquids.
4. Ionic solids dissolve in water because water molecules can split up the lattice, so the ions are free to move in solution and they also conduct electricity.
C3.5 Covalent bonding
1. They share electrons with other atoms to form a pair.
2. Strongly attracts the two atoms, forming a covalent bond.
3. Acts only between two atoms in its bonds. So covalent compounds consist of small molecules.
  1. Sometimes the molecule may contain a double or triple covalent bond. E.g. Oxygen.
4. Atoms in group 7 only need one more electron so they form a single covalent bond. Group 6 need 2, so they form 2 covalent bonds. Group 5 form 3 and group 4 make 4.
C3.6 Structure of simple molecules
1. Intermolecular forces
  1. Low melting and boiling points.
  2. Covalent bonds are very strong, so atoms within a covalent molecule are tightly packed together. Each molecule is separate from its neighbour and so simple molecules have little attraction for each cell their.
  3. Attraction between molecules are intermolecular forces, which are weak in simple bonds. Not slot of energy is needed to overcome them.
    1. These forces are overcome when melting or boiling a substance.
  4. These increase with the size of the molecule, larger molecules have higher melting and boiling points.
2. Polymers
  1. Polymers have very large molecules, as they are made up of many small molecules that covalently bond to each other forming long chains.
  2. Solid at room temperature as intermolecular forces are relatively strong.
  3. Simple molecules don't conduct electricity, as there is no overall charge.
C3.7 Giant covalent structures
1. Diamond from huge networks of atoms held together by strong covalent bonds, in giant covalent structures.
2. Requires a lot of energy to break down the structure of these, and so substances have very high melting points.
3. Diamond is a form of carbon with giant covalent structures.
  1. Every carbon atom forms strong covalent bonds with four other carbon atoms, si it is very hard, with a very high melting point.
4. Diamond doesn't conduct electricity .
  1. Graphite, Silicon dioxide have giant covalent structures.
5. In graphite, carbon atoms from three strong covalent bonds. Hexagonal rings, which are arranged in giant layers. No covalent bonds between layers, only intermolecular forces which slide over each, making graphite soft and slippery.
  1. There is a delocalised electron, which allows carbon to conduct Heat and electricity.
C3.8 Fullerenes and graphene
1. Fullerenes have the structure where carbon atoms join together to make large hollow shapes, in hexagonal, pentagonal or heptagonal rings.
2. The first one to be discovered is buckminsterfullerene, containing 60 carbon atoms in a spherical shape.
3. Fullerenes are used in drug delivery to the body, lubricants and catalysts.
4. Cars on nanotubes are cylindrical fullerenes.
  1. Used to reinforce composite materials for making tennis rackets. They have a delocalised electron giving them a high electrical conductivity.
5. Graphene is a single layer of graphite, hexagonal rings one carbon atom thick.
6. Good conductor of electricity, low density and is incredibly strong for its mass. These properties make it useful in electronics and composites.
C3.9 Bonding in metals
1. Atoms in a metallic element are the same size.
2. Form giant structures in which layers of atoms are arranged in regular patterns.
3. When metals are packed together, the electrons in the highest energy level delocalise and move freely between atoms.
4. Producing a lattice of positive ions in moving electrons.
5. The delocalised electrons strongly attract positive ions held together in giant structures.

Siguiente

C3 Structure and bonding

Descripción

Resumen del Recurso

Similar

	Creado por Alfie Mutch hace casi 7 años