Question

Name each of the following oxides. Assuming that the compounds are ionic, what charge is associated with the metallic element in each case? (a) \(\mathrm{NiO}\), (b) \(\mathrm{MnO}_{2}\), (c) \(\mathrm{Cr}_{2} \mathrm{O}_{3}\), (d) \(\mathrm{MoO}_{3}\).

Short answer

The given oxides can be named and their metallic element charges determined as follows: (a) \(\mathrm{NiO}\): Nickel Oxide; Ni: +2 (b) \(\mathrm{MnO}_{2}\): Manganese Dioxide; Mn: +4 (c) \(\mathrm{Cr}_{2} \mathrm{O}_{3}\): Chromium (III) Oxide; Cr: +3 (d) \(\mathrm{MoO}_{3}\): Molybdenum (VI) Oxide; Mo: +6

Step-by-step solution

Name each oxide

Using the periodic table, we can name the given oxides as follows: (a) \(\mathrm{NiO}\): Nickel Oxide (b) \(\mathrm{MnO}_{2}\): Manganese Dioxide (c) \(\mathrm{Cr}_{2} \mathrm{O}_{3}\): Chromium (III) Oxide (d) \(\mathrm{MoO}_{3}\): Molybdenum (VI) Oxide

Determine the charge of metallic elements

We can determine the charge of the metallic elements within each ionic compound using their corresponding oxidation states. We'll use the fact that the total charge of the compound is zero. (a) In \(\mathrm{NiO}\): Oxygen has a charge of -2. To balance the total charge, Nickel must have a charge of +2. Ni: +2 (b) In \(\mathrm{MnO}_{2}\): Each oxygen atom has a charge of -2, and with 2 oxygen atoms, the total negative charge is -4. To balance the total charge, Manganese must have a charge of +4. Mn: +4 (c) In \(\mathrm{Cr}_{2} \mathrm{O}_{3}\): Each oxygen atom has a charge of -2, and with 3 oxygen atoms, the total negative charge is -6. To balance this, the Chromium ion carries a charge of +3 (we divide the total positive charge by the number of metallic elements). Cr: +3 (d) In \(\mathrm{MoO}_{3}\): Each oxygen atom has a charge of -2, and with 3 oxygen atoms, the total negative charge is -6. To balance the total charge, Molybdenum must have a charge of +6. Mo: +6 The charges of the metallic elements in each oxide are as follows: (a) Ni: +2 (b) Mn: +4 (c) Cr: +3 (d) Mo: +6