Changes

*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]].H₂SO₄: [[Sulphuric Acid]] with two [[Hydrogen]] [[atom]]s, one [[Sulphur]] [[atom]] and four [[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.