Fundemental ideas in Chemistry

 A substance that is made up of one sort of atom is called an element.

There are about 100 different elements.

Elements that are in the same groups have simillar properties.

Atoms have a central nucleus, which is made up of protons and neutrons and around which there are electrons.

Charge

Protons +1

Neutrons 0

Electrons -1

Atoms have no overall charge as the no. of protons in the nucleus is equal to the no. of electrons.

The number of protons in an atom is it's atomic number.

The sum of protons and neutrons in an atom is it's mass number.

Inner-shell has a maximum of two electrons.

Other shells have a maximum of eight electrons.

Elements in the same group have the same number of electrons in the outer shell.  This gives them similar chemical properties.

The elements in group 0 of the periodic table are called the noble gases. They are unreactive because they have a stable electronic arrangement (full outer shell)

When elements react their atoms join together to form compounds. This involves giving, taking or sharing electrons.

The bond between a metal and a non-metal is called ionic.

The bond between two non-metals is called covalent.

No atoms are lost or made during a chemical reaction.

Mass of products equals mass of reactants.