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Writing Names and Formulas of Binary Ionic Compounds

SCIENCE INQUIRY
GoalDemonstrate your ability to write the names and formulas of chemical compounds and your ability to distinguish between ionic and molecular compounds.
What to Do

In the spaces below, record your answers to the questions in Investigation 2-A: Writing Names and Formulas of Binary Ionic Compounds.

1. Circle the binary compounds in the following list.

(a) HClYes

(c) MgCO3No

(d) hydrogen sulfideYes

(e) sodium hydrogencarbonateNo

2.(a)Which types of elements combine to form binary ionic compounds?

Metals and Nonmetals.

(b) Which types of elements combine to form binary molecular compounds?

Nonmetals and Nonmetals

3. Identify whether each name or formula represents an ionic or molecular substance.

(a) sodium sulfideIonic

(b) PCl3Molecular

(c) nitrogen dioxideMolecular

(d) zinc oxide Ionic

(e) MgI2 Ionic

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Writing Names and Formulas of Binary Ionic Compounds(continued)

SCIENCE INQUIRY

4. Complete the following table.

Element / Anion
Name / Symbol / Name / Symbol
fluorine / F / fluoride / F–
chlorine / Cl / chloride / Cl-
bromine / Br / bromide / Br-
oxygen / O / oxide / O2-
sulfur / S / sulfide / S2-
nitrogen / N / nitride / N3-

5. Complete the following table.

Formula / Total charge on cation(s) / Total charge on anion(s) / Correct () or incorrect (X) formula? / Correct formula and name of compound
(a) LiO / +1 / -2 / X / lithium oxide
Li2O
(b) MgO / +2 / -2 / Yes / magnesium oxide
(c) K2S / +2 / -2 / Yes / potassium sulfide
(d) AlBr3 / +3 / -3 / Yes / aluminum bromide
(e) NaN3 / +1 / -9 / X / sodium nitride
Na3N

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Writing Names and Formulas of Binary Ionic Compounds(continued)

SCIENCE INQUIRY

6.Work through the examples on page 49 of your SCIENCEFOCUS 10 textbook. In point form, outline how to determine the formula of a compound.

7.Complete the following table to write the formula of each compound.

Name of compound / Cation / Anion / Formula
(a) beryllium fluoride / Be2+ / F- / BeF2
(b) sodium nitride / Na+ / N3- / Na3N
(c) calcium sulfide / Ca2+ / S2- / CaS
(d) aluminum chloride / Al3+ / Cl- / AlCl3
(e) lithium oxide / Li+ / O2- / Li2O
(f) magnesium nitride / Mg2+ / N3- / Mg3N2
(g) gallium sulfide / Ga3+ / S2- / Ga2S3
(h) barium bromide / Ba2+ / Br- / BaBr2

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Writing Names and Formulas of Binary Ionic Compounds(continued)

SCIENCE INQUIRY

8.Copy the examples on page 49 of your textbook, and explain them to a partner so you will remember how they work.

9. Complete the following table to find the charge on the cation in these compounds. Decide if your answers are reasonable before you move on to step 10.

Compound / Charge on cation
(a) Cu2S / +1
(b) Cr2O3 / +3
(c) PbO2 / +4
(d) NiCl2 / +2
(e) CrN / +3
(f) HgO / +2

10.Complete the following table by adding the missing Stock system names.

Formula / Ion / Name
FeCl3 / Fe3+ / iron(III) chloride
FeO / Fe2+ / iron (II) oxide
Cu2S / Cu+ / copper (I) sulfide
PbO2 / Pb4+ / lead (IV) oxide

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Writing Names and Formulas of Binary Ionic Compounds(continued)

SCIENCE INQUIRY

11. Complete the following table to write the chemical formula for each compound.

Name of compound / Cation / Anion / Chemical formula
(a) copper(I) oxide / Cu+ / O2- / Cu2O
(b) lead(IV) bromide / Pb4+ / Br- / PbBr4
(c) iron(III) sulfide / Fe3+ / S2- / Fe2S3
(d) nickel(III) fluoride / Ni3+ / F- / NiF3
(e) manganese(IV) sulfide / Mn4+ / S2- / MnS2
Analyze

1. Explain why you must use the Stock system to name ionic compounds containing transition metals. In which cases do you not need to use the Stock system to name an ionic compound? Explain your answer.

The Stock system must be used for ionic compounds containing transition metals that have more than one possible charge in order to indicate which ionic version (charge) is in the compound. This system is not needed for metal ions of groups 1 and 2, nor is it needed for the transition metals that have only 1 ionic charge. If the metal only has one ionic charge, there is no need to mention it.

2.There is something wrong with the name written beside each of the following compounds. In each case, explain why the name is wrong, and then write the correct name.

Formula / Incorrect name / Explanation / Correct name
(a) Ti2O3 / dititanium trioxide / Ionic compounds do not use prefixes to indicate # of atoms. Also, charge of Ti must be mentioned / titanium (III) oxide
(b) NaCl / sodium(I) chloride / It is not necessary to mention the charge of the sodium ion. It only has one possible charge. / sodium chloride
(c) CuCl2 / copper chloride / Copper has more than 1 possible ionic charge. The version in the compound must be mentioned in the name. / copper (II) chloride
(d) NO2 / nitrogen(IV) oxide / Molecular compounds need to have prefixes to indicate the number of atoms of each type in the molecule. Also, nitrogen is not a +4 charge. / nitrogen dioxide

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