## 2A.24

Ami_Pant_4G
Posts: 106
Joined: Sat Aug 24, 2019 12:17 am

### 2A.24

On the basis of the expected charges on the monatomic ions, give the chemical formula of each of the following compounds: (a) magnesium arsenide; (b) indium(III) sulfide; (c) aluminum hydride; (d) hydrogen telluride; (e) bismuth(III) fluoride.

Can someone please explain how to find a and b? Thanks in advance.

Posts: 51
Joined: Sat Aug 24, 2019 12:16 am

### Re: 2A.24

a) Mg's preferred oxidation state is +2 while As's preferred oxidation state is -3. To make the molecule neutral, the formula is Mg3As2.
b) The (III) after In indicates it has a +3 oxidation state. S's preferred oxidation state is -2. Thus, to make the molecule neutral, the formula is In2S3.

Myka G 1l
Posts: 100
Joined: Fri Aug 30, 2019 12:17 am

### Re: 2A.24

You just have to use the expected charges of the individual ions to figure out the chemical formula. For a the charge of Mg is 2+ and As is 3- so the chemical formula would be Mg3As2 because you want the charges to cancel out. For b the charge of In is 3+ as indicated by the Roman numerals and the charge of S is 2- so the chemical formula would be In2S3.

Vuong_2F
Posts: 90
Joined: Sat Sep 14, 2019 12:17 am

### Re: 2A.24

a) magnesium has a charge of +2 and arsenic has a charge of -3.
Therefore, you will need 3 of Mg and 2 of As to balance out the charges, which gives you the formula $Mg_{3}{As_{2}}$

b) The charge of indium is given as (III), or +3, and sulfur has a charge of -2.
Therefore, you will have the formula $In_{2}{S_{3}}$