OCR Gateway Chemistry - C1

What are the three states of matter?

Solid, liquid, gas

Describe the arrangement and movement of particles in solids

The particles are packed closely in a regular arrangement. The particles vibrate in fixed positions

Describe the arrangement and movement of the particles in liquids

The particles are close together but able to move past each other. The particles vibrate and move past each other

Describe the arrangement and movement of the particles in gases

The particles are far apart with no regular arrangement. The particles vibrate and move freely

How do the relative energies of particles in a solid, liquid and gas compare?

Particles in a solid have the least energy. Particles in a gas have the most energy

What is the name for the state change from solid to liquid and vice versa?

Solid to liquid: melting

Liquid to solid: freezing

What is the name for the state change from liquid to gas and vice versa?

Liquid to gas: evaporation

Gas to liquid: condensation

Describe the intermolecular forces between particles in solids, liquids and gases

Solids: Strong forces of attraction between particles

Liquids: Weaker forces of attraction than solids

Gases: Weakest intermolecular forces between particles

Describe what happens, in terms of particles, when a solid is heated and melts into a liquid

When heated, particles absorb thermal energy and convert it into kinetic energy. The particles in the solid vibrate more, causing the solid to expand until the structure breaks and the solid turns to a liquid

Describe what happens, in terms of particles, when a liquid is heated and evaporates into a gas

When heated, the particles in a liquid expand. Some particles on the surface gain enough energy to overcome the intermolecular forces and evaporate. At the boiling point, all of the liquid particles gain enough energy to evaporate

Why do solids, liquids and gases expand when heated?

When a substance is heated the molecules vibrate faster. This causes the space between the atoms to increase

What is meant by the terms element and compound?

Elements are substances made up of only one type of atom.

Compounds are made up of atoms of different elements

What was Dalton's atomic theory?

All matter is made up of atoms.

Atoms cannot be created, divided, or destroyed.

All atoms of the same element are identical but different from atoms of other elements.

Atoms join with other atoms to make new substances

What discovery changed Dalton's model of the atom?

The discovery of subatomic particles

Describe the atomic model of JJ Thompson

Plum pudding model:

Negatively charged electrons scattered in a positively charged material

Describe Rutherford's model of the atom

Mass is concentrated in the centre of the atom (nucleus)

Mostly empty space

Describe the structure of an atom

A small nucleus made up of protons and neutrons. Electrons orbit the nucleus in shells

What are the relative masses of a proton, neutron and electron?

Proton - 1

Neutron - 1

Electron - 0

What are the relative charges of a proton, neutron and electron?

Proton: +1

Neutron: 0

Electron: -1

What is an ion?

An atom with a positive or negative charge

How is an ion formed?

When an atom gains or loses an electron

What does the atomic number of an element tell you?

The number of protons

What is the mass number?

The total number of protons and neutrons in the nucleus of an atom

What are isotopes?

Atoms of the same element with different numbers of neutrons

Why do atoms have the same number of protons and electrons?

To keep the overall charge of the atom at 0