GCSE CHEMISRTY COMBINED SCINCE

WHAT ARE ELEMENTS ?

An element is a substances made from atoms with the same number of protons in the nuclues. 

Each elements is represnted by a chemical symbol which;

consists of one or two letters

always starts with a capital letter,

with any other letter in lower case

for example mercury os Hg. you can find the symbols for the elments in the peridoic table. 

What is an atoms?

an atoms is the smallest particle of an element that still has chemical properties.

A molecule consits of two or more atoms chemcically joined togather.

what state are most elements at room tempreture?

most elements are gases at room tempreture exist as molecules with two atoms. They are shown as chemical formlae such as;

H 2, N 2, O 2, F 2, Cl 2 

compund 

what is a compund?

A compunds consits of two or more diffrent elements chemically joined toagther.

the chemical formula for Methane is CH . Each methane molecule has 

one carbon atom (no number  in the formula) 

four hydrogen atoms (shown in number) 

atoms have two or more elements chemical joined

(1 + 4= 5 atoms in total)