[Remah]

what is the oxidation number of hydrogen in a given compound that contains three elements (metal, a non-metal and hydrogen) ? is it will be H+ or H- ? for example - NaBH .

Thank u 

[Arkcon]

Greetings, Remah:, I'd like to welcome you and all the new students to the Chemical Forums.  But I'd like to as you to trouble yourself to read our Forum Rules{click}. You already accepted them when you signed up for our forum, and they apply to you, whether you agree with them or not, or even if you're unaware of them. 

We want to see your work, and then, we want to give you hints, so that you learn for yourself.  Unfortunately, what you've asked us for is a simple definition.  I Goggled the answer in just a few seconds, and you likely have a textbook, with an index, that will lead you to the answer shortly.

Why not try salvaging this thread by coming up with an example question that uses this or similar concepts, and seeing if you can solve it.  You will need this practice when exam time comes.

[Vidya]

what is the oxidation number of hydrogen in a given compound that contains three elements (metal, a non-metal and hydrogen) ? is it will be H+ or H- ? for example - NaBH .

Thank u 

Check how H behaves in the presence of metal and in the presence pf non -metals.Do you know anything about hydride ion ?

[Flatbutterfly]

Find in your text the two ways to assign oxidation numbers in TM cmplxs.
Use the less common one for M-H or E-H.

[Flatbutterfly]

The second method is that the pair of electrons in covalent bonds is assigned to the more electronegative element.  See what happens in HF, H2O, NH3 versus "BH3", NaH