writing chemical formulas that contain polyatomic ions?

Question

if u know what I'm talking about, then plz pay attention. This is 8th chemistry. so anyway.....this is about writing chemical formulas that contain polyatomic ions.grade chemistry. anyway, this is about
Example:

The chemical formula for a compound composed of calcium and a hydroxide ion is Ca(OH)2.

1. Ca +2 OH -1
2. Ca +2 OH-1
3. Ca(OH)2.

my question is:

the ion for Oxygen is -2
the ion for Hydrogen is -1.

so why doesnt (OH)-2 turn into (OH)-3?

Answer 1

No, you are wrong: O is -2 but H is +1 (H is -1 in hydrures, like KH)
So -2+1=-1 in (OH).

Remember that in inorganic chemistry, H is always +1, except when combined with an always positive element (basically metals from groups 1 and 2: K, Ca, Na... then it's -1)

Answer 2

Calcium hydroxide is Ca(OH) subscript 2

becuase the polyatomic ion hydroxid (OH) has a negative charge of -1, when written by itself, it is OH-

So, since calcium (Ca) has a charge of +2 and OH has a charge of -1, then it becomes Ca1OH2, but it is written as CA(OH)2 because the 1 is understood.

(for most things, you can flip the charges of the different parts (2 for Ca and 1 for OH) and make them the subscripts.)

hope this helps!

p.s. i'm taking chemistry now, so if you need any more help, just send me an email: [e-mail].

Answer 3

The charge for H is +1. The math works out

Answer 4

In some cases Hydrogen is +1., but in some its -1

In the hydroxide formula (OH) Hydrogen is +1

Thats why Hydroxide is -1