CH1001 Lecture Notes - Lecture 2: Chemical Formula, Ion, Hydride
Document Summary
Show the relative number of each type of atom present in a substance. H2o (note: a subscripted number refers only to the atom immediately proceeding it). A chemical formula that refers to a discrete molecule. Element further to the left of the periodic table appears first. If both elements are from the same group the lowest element appears first. In ionic compounds the cation is written first followed by the anion. Writing chemical formulae for compounds containing more than two elements. requires some knowledge of the bonding within the compound. Show a bond between atoms as either a pair of dots or a line. Show atoms as spheres and bonds as sticks. Accurate angles and relative sizes, but distances are exaggerated. Accurately scaled-up versions of molecules, but do not show bonds. Show the ball-and-stick model within the space-filling shape. Colour the regions of high electron charge red. Colour the regions of low electron charge blue.
