Changes

: Some '''chemical formulae''' have brackets which indicate that the [[element]]s in the bracket are multiplied by the number after the bracket.*MgBr₂: [[Magnesium Bromide]] with one 1 [[Magnesium]] [[atom]] and two 2 [[Bromine]] [[atom]]s.*CO₂: [[Carbon Dioxide]] with one 1 [[Carbon]] [[atom]] and two 2 [[Oxygen]] [[atom]]s.*Li₂O: [[Lithium Oxide]] with two 2 [[Lithium]] [[atom]]s and one 1 [[Oxygen]] [[atom]].H*Al(OH)₃: [[Aluminium Hydroxide]] with 1 [[Aluminium]] [[atom]], with 3 lots of OH; 3 [[Oxygen]] [[atom]]s and 3 [[Hydrogen]] [[atom]]s.*Al₂SO(CO₄₃)₃: [[Sulphuric AcidAluminium Carbonate]] with two 2 [[HydrogenAluminium]] [[atom]]s, one and 3 lots of CO₃; 3 [[SulphurCarbon]] [[atom]] s and four 9 [[Oxygen]] [[atom]]s.

 Some '''chemical formulae''' are written with the [[element]]s at specific points, not all grouped together, to show where different [[element]]s are [[Chemical Bond|bonded]]. This is called a [[Structural Formula|structural formula]].*CH₃COOH: [[Ethanoic Acid]] with two 2 [[Carbon]] [[atom]]s, two 2 [[Oxygen]] [[atom]]s and four 4 [[Hydrogen]] [[atom]]s. This shows that one [[Carbon]] is [[Chemical Bond|bonded]] to three [[Hydrogen]] [[atom]]s while the other [[Carbon]] is [[Double Bond|double bonded]] to one [[Oxygen]] and has a [[Single Bond|single bond]] with an [[Oxygen]], which itself it bonded to a [[Hydrogen]].*CH₃CH₂COOH: [[Propanoic Acid]] with three [[Carbon]] [[atom]]s, two [[Oxygen]] [[atom]]s and 6 [[Hydrogen]] [[atom]]s.

| style="height:20px; width:200px; text-align:center;" |[[Propanol]] or [[Propan-1-ol]] has 3 [[Carbon]] [[atom]]s and 8 [[Hydrogen]] [[atom]]s and 1 [[Oxygen]] atom. This has the same '''chemical formula''' as [[Propan-2-ol]] but a different shape. The '''forumula''' This may be written as with the [[Structural Formula|structural formula]] '''CH₃⋅CHCH₂⋅CHOHCH₂OH''' to show where the OH group is attached.| style="height:20px; width:200px; text-align:center;" |[[Isopropyl Alcohol]] or [[Propan-2-ol]] has 3 [[Carbon]] [[atom]]s and 8 [[Hydrogen]] [[atom]]s and 1 [[Oxygen]] atom. This has the same '''chemical formula''' as [[Propan-1-ol]] but a different shape. The '''forumula''' This may be written as with the [[Structural Formula|structural formula]] '''CH₃⋅CHOH⋅CHCHOHCH₃''' to show where the OH group is attached.