CHEMISTRY – Yeah, don’t you wish it was as easy as this rule? The rules for writing chemical formulas, I mean. But no, it seems like there are about 50 million, and you have to keep them all straight! What is the one thing that would help you the most with this? Memorizing polyatomic ions? Memorizing rules for naming? More practice?
Here’s my best advice – first, memorize what you are supposed to memorize – polyatomic ions, rules, etc. Next, organize your notes into what you do for ionic compounds, those with metals and polyatomic ions, and what you do for molecules, those with only nonmetals and metalloids. Next, analyze every single compound you have to name or write a formula for – is it ionic? then you only use the Stock system. Is it a molecule – then you can use the Stock system or prefixes. Do you see what I mean?
Don’t just try to wing it! You’ve got the tools you need, now go use them!!