What are the chemical formulas for barium oxide and lead(II) phosphate?

1 Answer
Meave60
Sep 19, 2016

Refer to the explanation.

Explanation:

Barium oxide

Barium oxide has the formula BaO. It's an ionic compound, so its formula represents the lowest whole number ratio of elements in the compound. So Ba2O2 should be reduced to BaO.

Lead (II) phosphate

The formula for the lead (II) ion is Pb2+. The formula for the phosphate ion is PO3−4. An ionic compound is neutral, so the total positive charge must be equal to the total negative charge. An easy way to determine the formula unit of an ionic compound is to use the crisscross method, where the size of each ion becomes the subscript of the oppositely charged ion. So the correct formula for lead (II) phosphate is Pb3(PO4)2.

![http://www.showme.com/sh/?h=6m1sZhg](useruploads.socratic.orguseruploads.socratic.org)

Notice that when there is more than one polyatomic ion in the formula, it is placed inside parentheses and its subscript is written outside of the parentheses.

Nickel (III) sulphate is the correct name for Ni2(SO4)3

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