deducing formulae Flashcards
1
Q
what is the formula of aluminium sulfide
A
step 1
finding the group number for each element
aluminium -3
sulfur would be 2 as it is a non-metal so it is 8-6=2
step 2
swap the numbers
so the answer would be Al2S3
2
Q
what is the formula of calcium bromide?
A
step 1
write the formulae of the ions Ca+ and Br-
step 2
balance the charges. we need two Br- to balance on Ca2+
step 3
write the formulae with the metal ion first CaBr3
3
Q
what are state symbols
A
gas (g), liquid (l), solid(s)
4
Q
what is an ionic equation
A
an equation showing only those ions and molecules taking part in the reaction.
5
Q
what are spectator ions
A
ions which do not take part in a reaction.