## 2A.23 question

Aashka Popat 1A
Posts: 50
Joined: Sat Sep 07, 2019 12:16 am

### 2A.23 question

This is the question: 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.

I don't know how to approach this problem, could anyone explain how to find the formula of part a? Thanks!

Ashley Kao 1H
Posts: 50
Joined: Thu Jul 25, 2019 12:16 am

### Re: 2A.23 question

I believe the chemical formula for Magnesium Arsenide is Mg3As2.

Andrew Pfeiffer 2E
Posts: 101
Joined: Sat Sep 28, 2019 12:16 am

### Re: 2A.23 question

Magnesium arsenide: As2Mg3

Indium III Sulfide: In2S3

Aluminum hydride: AlH3

Aluminum telluride: H2Te

Bismuth III Flouride: BiF3

Posts: 104
Joined: Fri Aug 09, 2019 12:16 am

### Re: 2A.23 question

In order to find the equation you have to look at the charges for magnesium ions and for arsenic ions. Magnesium ions have a charge of 2+ and arsenic ions have a charge of 3- so in order to balance the charges there must be three magnesium atoms and 2 arsenic atoms.

Andrew Pfeiffer 2E
Posts: 101
Joined: Sat Sep 28, 2019 12:16 am

### Re: 2A.23 question

For a further explanation of part A, Magnesium usually gives up 2 valence electrons, while Arsenic usually takes 3 valence electrons. Thus, two Arsenic atoms would take 6 valence electrons, and 3 Magnesium atoms would give 6 valence electrons.

Maya Beal Dis 1D
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Joined: Sat Aug 17, 2019 12:16 am
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### Re: 2A.23 question

This question asks you to determine the empirical formula of the ionic compound that would be formed if these two elements were to form an ionic bond. To do this you should find each element on the periodic table and determine the charge that element usually assumes based on it's valence electrons. Then you must have a net charge of zero between the atoms in the ionic bond, so you multiply each atom by the amount that is needed to balance the charges.