Write the formulas for the following compounds:?

Question

Lead(IV) Oxide

Chromuim(III) Chloride

Copper(II) Chloride

Iron(III) Bromide

Mercury(I) Sulphide

Also, Name the following compounds. Include the numeral:

Cu2O

MnCl2

PbO

Fel3

AuBr3

Answer 1

PbO2

CrCl3

CuCl2

Fe2Br3

Hg3S

cupric I oxide

manganese II chloride

lead II oxide

iron III iodide

gold VI bromide

im not sure about the last one ... look it up.

Answer 2

Since each of these species is uncharged, the oxidation numbers of each of the atoms that make up the molecule must add to equal zero.  The Roman Numeral given after the name of the metal is equal to the oxidation state of the metal.  Also, the oxidation states of the ions attached to the metal are equal to the charge on that ion if it was isolated from the metal (example: sulfide has a charge of 2-, so the oxidation state is -2.  Note the difference in notation between a charge and an oxidation state.).

With these ideas in mind, let's work on your list.

Lead(IV) oxide.  Oxide (O) has a charge of 2- and the oxidation state on lead in this compound is +4.  To have a total oxidation state of zero, this compound must have 2 oxide ions to balance the +4 oxidation state of lead.  Therefore, your answer is PbO2.

Halogen ions such as chloride and bromide have a charge of 1- (oxidation state of -1).  With this in mind, your next answers are the following:

Chromium(III) chloride = CrCl3

Copper(II) chloride = CuCl2

Iron(III) bromide = FeBr3

Recall from above that sulfide has a charge of 2-, so since the oxidation state of Mercury is +1, two mercury atoms are necessary to balance the oxidation state of sulfide.

Mercury(I) sulfide = Hg2S

To name compounds if given the molecular formula, just work backwards.  Since we know that O has an oxidation state of -2, if two coppers are necessary to end up with an oxidation state of zero, then each copper atom must have an oxidation state of +1.

Cu2O = Copper(I) oxide (Notice that the first term is capitalized, but not the second.  This is true for all compounds with names that contain two words.)

Use this same line of reasoning to name the other four compounds:

MnCl2 = Manganese(II) chloride

PbO = Lead(II) oxide

FeI3 = Iron(III) iodide

AuBr3 = Gold (III) bromide

Hope this helps.