help with highschool chemistry please?

Question

I need help with Highschool chemistry-
my teacher refuses to teach me because it was my responsibility to attend class in the first place :(
i really need to learn how to do this as i am really behind

how do i write the chemical formula for molecules?
for example:
copper(II) nitrate


and how do i name chemical formulas?
for example:
Cr(CH3COO)2

i understand that LiF would be lithium monoflouride but what i dont understand is how the number of protons and etc effect it

i hope this is clear and thanks for any help in advance

gahh im trying my hardest to understand this but i dont get it

would strontium hydroxide be Sr(H)2 ?

because strontium is Sr2+
and you need two hydrogens to balance it out?

Answer 1

First off, you will need to memorize certain things. For example, you will need to know that nitrate is NO3- and acetate is CH3COO-.

To write the chemical formula for an ionic compound such as copper(II) nitrate, here's how:

The first word, copper (II), tells you that the positive ion is copper (Cu) and the oxidation state is 2+. Thus your positive ion is Cu2+.

The second word, nitrate, tells you that your negative ion is NO3-. Since you need two nitrates for every copper (II) for the charges to balance out, your formula is Cu(NO3)2.

For the second question, you need to identify the positive and negative ions. The negative ion is CH3COO-, which is acetate. Since there are two of them, that means that the positive ion must be Cr2+ for the charges to balance. Thus the positive ion is called chromium (II), and the total name is chromium (II) acetate.

For the last question the name of LiF is lithium fluoride. Mono is unnecessary because lithium always exists in compounds as Li+ and fluorine as F-, so there's no other possible combination of the two.