CHEM1011 Lecture Notes - Lecture 2: Bromine Trifluoride, Sodium Bromide, Hydrogen Peroxide

• School: UNSW, UNSW Sydney
• Department: Chemistry
• Course: CHEM1011
• Professor: Steve Colbran

Document Summary

Chemical formulae - binary compounds: bi(cid:374)ary co(cid:373)pou(cid:374)ds. Binary compounds contain exactly two different elements. Element further to the left of the periodic table appears first: kcl, al(cid:1006) (cid:1007) Hydrogen is the exception to this rule: lih, nh(cid:1007), h(cid:1006)o(cid:1006), hcl. Hydrogen written last except when combined with a group 16 or 17 element. If both elements are from the same group the lowest element appears first: ic, brf(cid:1007) Chemical formulae - ionic compounds: bi(cid:374)ary co(cid:373)pou(cid:374)ds. In ionic compounds the cation is written first followed by the anion: nabr, mgcl(cid:1006) Reminder: a subscripted number refers onl< to the atom immediately preceding it unless the number comes after a species enclosed in brackets. Chemical formulae beyond binary compounds: writi(cid:374)g chemical formulae for compounds containing more than two elements requires some knowledge of the bonding within the compound, categorise as: Write the cation followed by the anion, e. g. , ca(no3)2. Note the positioning of the brackets around the no3-