particles

• Atom


  The smallest unit of an element that retains its properties. It consists of a nucleus, which contains protons and neutrons, and electrons that orbit the nucleus.
• Element


  A substance made up of atoms. Each element is characterized by its unique number of protons in the nucleus.
• Nucleus


  The central part of an atom that contains protons and neutrons. It is surrounded by orbiting electrons.
• Electron


  A negatively charged particle that orbits the nucleus of an atom. Electrons are involved in chemical bonding and determine the atom's reactivity.
• Molecule


  A chemically bonded group of atoms. It can be composed of atoms of the same element or different elements.
• in solids, the particles are in fixed arrangement
• in solids the particles vibrate
• there are strong forces between solid particles
• solids have a definite shape
• solids have a definite shape
• in liquids, the particles are close but can move over eachother
• in liquids the particles move randomly
• there are weak forces between liquid particles
• liquids have no definite shape
• in gasses, the particles are far apart
• in gasses, the particles move randomly and have very weak forces between particles
• by increasing or decreasing the temperature of a substance, you can change its state of matter
• you could change a solid to a liquid by melting
• you could change from a liquid to a gas by boiling
• you could go from a gas to a liquid by condensing
• liquid to solid by freezing
• you could go from solid to gas using sublimation
• when changes of state are made, mass is always conserves
• evaporation is when a liquid turns to a gas, but only at the surface of a liquid
• only the particles on the surface have enough energy to turn into gas
• if you heat a solid, you provide the particles with more energy, causing them to vibrate more. Eventually when you reach the solid's melting point, the particles gain enough energy to break free of their bonds, turning them into a liquid
• if you heat up a liquid, the particles will gain more energy and move around faster, causing them to weaken the bonds. once reaching the boiling point, the particles have enough energy to break the bonds completely and so boiling or evaporating into a gas.
• gas particles move in random directions in a straight line constantly
• if you cool down a gas, they wont have enough energy to overcome forces, and so bonds will start to form between the particles, condensing into a liquid.
• if you cool down a liquid, even more bonds will start to form as the particles wont have enough energy to overcome the forces of attraction between them, fixing the particles in place and freezing the liquid to a solid.
• the pressure of a gas is due to the particles colliding with eachother and the walls on the container
• if you increase the volume of the container but keep the temperature constant, the pressure decreases as particles now travel a further distance before colliding
• if you increase the temperature whilst keeping the volume constant, you increase the pressure as particle collisions increase