Unit 5 Lesson 2: Naming and Writing Formulas for Ionic Compounds

How do you determine the formula and name of a compound with a polyatomic ion?

To write the formula for a compound with a polyatomic ion, first write the symbol(or formula) for the cation followed by the symbol(or formula) for the anion. Then add subscripts as needed to balance the charges.

How do you determine the formula and name of a binary ionic compound?

To write the formula of a binary ionic compound, first write the symbol of the cation and the the anion. Then add subscripts as needed to balance the charges.

When do you use parentheses in writing a chemical formula?

When the compound contains more than one of a particular polyatomic ion.

Write the formula for these binary ionic compounds. a. beryllium chloride b. cesium sulfide c. sodium iodide d. strontium oxide

a. BeCl2 b.Cs2S c. NaI d. SrO

Write the formula for these compounds containing polyatomic ions. a. chromium (III) nitrite b. sodium perchlorate c. magnesium hydrogen carbonate d. calcium acetate

a. Cr(NO2)3 b. NaCIO4 c. Mg(HCO3)2 d. Ca(C2H3O2)2

Which of the following formulas are incorrect? Explain your answer.

a. incorrect; charges are not balanced, MgSO4 b. incorrect; anion symbol should be Rb3As c. incorrect; charges are not balanced, BeCI2

What condition must be met when writing a formula for an ionic compound?

The charge of the ions must balance.

What are the advantages and disadvantages of common names?

Most common names do not tell you about the chemical composition of a compound. Many common names indicate other physical characteristics of the compound.

binary compound

a compound comprised of two elements; NaCi and Al2O3.

Name the following ionic compounds: a. LiF b. SnS2 c. MnCO3 d. Sr(H2PO4)2

a. lithium fluoride b. tin(IV) sulfide c. manganese(II) carbonate d. strontium dihydrogen phosphate