Chemistry IGCSE

When a solid is heated and its particles vibrate so quickly that the force of attraction between them is no longer strong enough to hold them together.

When a liquid is cooled and its particles move so slowly that the force of attraction between them will hold them into a solid

When a liquid is heated and its particles move so quickly that they break all the foces of attraction and gaseous bubbles rise to the surface

When a gas is cooled and its particles move slowly enough that attractions between them hold them together as a liquid

When some very fast particles on the surface of the liquid have enough energy to break away to form a gas

Changing directly from a solid to a gas or vice-versa without involving any liquid on the way. eg. heating ammonium chloride in test tube or carbon dioxide (dry ice ).

The spreading out of particles in a gas or liquid

2 bits of cotton wool are soaked in concentrated ammonium solution, and hydrochloric acid. They are placed at the end of a long glass tube with rubber bungs at each end. After a while a white ring of ammonium chloride forms closer to the hydrochloric acid end. This proves that ammonia particles are lighter and faster .

Purple Potasium Manginate experiment. Keep diluting!

Fill the lower jar with bromine gas and upper jar with air. If lids are removed the brown bromine difuses with air and both jars are uniformly brown.

Number of protons in the nucleus of an atom

Number of protons +neurons in an atom

Atoms with the same number of protons but different number of neurons.

When an atom's nucleus is unstable, and radiation is released as it organises itself into a more stable form

Vertical columns in the periodic table