Atoms, elements and compounds - AQAChemical formulae of elements
Chemists use symbols and formulae to represent elements and compounds. Word equations and balanced chemical equations represent the changes that happen in chemical reactions.
A chemical formulaA combination of symbols that indicates the chemical composition of a substance. is used to represent an elementA substance made of one type of atom only. or compoundA substance formed by the chemical union of two or more elements. in balanced chemical equationA chemical equation written using the symbols and formulae of the reactants and products, so that the number of units of each element present is the same on both sides of the arrow..
The formula for most elements is just its chemical symbol. For example:
helium, He
lithium, Li
beryllium, Be
boron, B
carbon, C
neon, Ne
sodium, Na
magnesium, Mg
Some non-metal elements exist as moleculeA collection of two or more atoms held together by chemical bonds. that are made up of two atomThe smallest part of an element that can exist. joined together. The formulae of these elements are the element's symbol followed by a subscriptA letter or number written below the line. '2'. For example:
iodine, I2
bromine, Br2
chlorine, Cl2
fluorine, F2
oxygen, O2
nitrogen, N2
hydrogen, H2
A mnemonic can be used to remember these elements:
IBring Clay For Our New House.
Question
What are the chemical formulae of the elements neon, nitrogen and sodium?