Naming and writing formulas for ionic compounds worksheet | Live ... - Free Printable

Here is the complete solution for the worksheet “Names & Formulas for Ionic Compounds”, with explanations for each answer.

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## ✔ Left Column: Given Formula → Write Name

1) Na₂CO₃

Sodium carbonate
*Na⁺ (sodium ion) + CO₃²⁻ (carbonate ion). Charge balance: 2×(+1) + (-2) = 0.*

2) NaOH

Sodium hydroxide
*Na⁺ + OH⁻. Common strong base.*

3) MgBr₂

Magnesium bromide
*Mg²⁺ + 2 Br⁻. No Roman numeral needed — Mg has only one common charge (+2).*

4) KCl

Potassium chloride
*K⁺ + Cl⁻. Simple binary ionic compound.*

5) FeCl₂

Iron(II) chloride
*Fe²⁺ + 2 Cl⁻. Iron is transition metal → use Roman numeral to indicate charge.*

6) FeCl₃

Iron(III) chloride
*Fe³⁺ + 3 Cl⁻. Different charge than #5 → different Roman numeral.*

7) Zn(OH)₂

Zinc hydroxide
*Zn²⁺ + 2 OH⁻. Zinc usually has +2 charge → no Roman numeral needed.*

8) Be₂SO₄

⚠️ This formula is incorrect!
Correct formula for beryllium sulfate is BeSO₄ (Be²⁺ + SO₄²⁻ → 1:1 ratio).
But if forced to name as written:
Beryllium sulfate *(but should be BeSO₄, not Be₂SO₄)*

> *Note: Be₂SO₄ implies 2 Be²⁺ and 1 SO₄²⁻ → total charge +4 vs -2 → not balanced. Likely a typo.*

9) CrF₂

Chromium(II) fluoride
*Cr²⁺ + 2 F⁻. Chromium is transition metal → use Roman numeral.*

10) Al₂S₃

Aluminum sulfide
*Al³⁺ + S²⁻ → cross charges: Al₂S₃. Aluminum has fixed +3 charge → no Roman numeral.*

11) PbO

Lead(II) oxide
*Pb²⁺ + O²⁻. Lead is multivalent → use Roman numeral. (Pb⁴⁺ also exists → e.g., PbO₂ = lead(IV) oxide)*

12) Li₃PO₄

Lithium phosphate
*Li⁺ + PO₄³⁻ → 3 Li⁺ needed to balance. Lithium always +1.*

13) TiI₄

Titanium(IV) iodide
*Ti⁴⁺ + 4 I⁻. Titanium is transition metal → Roman numeral needed.*

14) Co₃N₂

Cobalt(II) nitride
*Co²⁺ + N³⁻ → least common multiple of charges: 3 Co²⁺ = +6, 2 N³⁻ = -6 → Co₃N₂. Cobalt is transition metal → Roman numeral.*

15) Mg₃P₂

Magnesium phosphide
*Mg²⁺ + P³⁻ → 3 Mg²⁺ = +6, 2 P³⁻ = -6. Magnesium has fixed +2 charge → no Roman numeral.*

16) Ga(NO₂)₃

Gallium nitrite
*Ga³⁺ + NO₂⁻ → 3 nitrite ions needed. Gallium has fixed +3 charge.*

17) Ag₂SO₃

Silver sulfite
*Ag⁺ + SO₃²⁻ → 2 Ag⁺ needed. Silver usually +1 → no Roman numeral.*

18) NH₄OH

Ammonium hydroxide
*NH₄⁺ + OH⁻. Polyatomic ions only.*

19) Al(CN)₃

Aluminum cyanide
*Al³⁺ + CN⁻ → 3 cyanide ions. Aluminum fixed +3.*

20) Be(CH₃COO)₂

Beryllium acetate
*Be²⁺ + CH₃COO⁻ → 2 acetate ions. Beryllium fixed +2.*

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## ✔ Right Column: Given Name → Write Formula

21) sodium phosphide

Na₃P
*Na⁺ + P³⁻ → 3 Na⁺ needed to balance.*

22) magnesium nitrate

Mg(NO₃)₂
*Mg²⁺ + NO₃⁻ → 2 nitrate ions needed.*

23) lead(II) sulfite

PbSO₃
*Pb²⁺ + SO₃²⁻ → 1:1 ratio.*

24) calcium phosphate

Ca₃(PO₄)₂
*Ca²⁺ + PO₄³⁻ → LCM of charges: 3 Ca²⁺ = +6, 2 PO₄³⁻ = -6.*

25) ammonium sulfate

(NH₄)₂SO₄
*NH₄⁺ + SO₄²⁻ → 2 ammonium ions needed.*

26) silver cyanide

AgCN
*Ag⁺ + CN⁻ → 1:1 ratio.*

27) aluminum sulfide

Al₂S₃
*Al³⁺ + S²⁻ → 2 Al³⁺ = +6, 3 S²⁻ = -6.*

28) beryllium chloride

BeCl₂
*Be²⁺ + Cl⁻ → 2 chloride ions needed.*

29) copper(I) arsenide

Cu₃As
*Cu⁺ + As³⁻ → 3 Cu⁺ needed to balance.*

30) iron(III) oxide

Fe₂O₃
*Fe³⁺ + O²⁻ → 2 Fe³⁺ = +6, 3 O²⁻ = -6.*

31) gallium nitride

GaN
*Ga³⁺ + N³⁻ → 1:1 ratio.*

32) iron(II) bromide

FeBr₂
*Fe²⁺ + Br⁻ → 2 bromide ions needed.*

33) vanadium(V) phosphate

V₃(PO₄)₅
*V⁵⁺ + PO₄³⁻ → LCM of charges: 3 V⁵⁺ = +15, 5 PO₄³⁻ = -15.*

34) calcium oxide

CaO
*Ca²⁺ + O²⁻ → 1:1 ratio.*

35) magnesium acetate

Mg(CH₃COO)₂
*Mg²⁺ + CH₃COO⁻ → 2 acetate ions needed.*

36) aluminum sulfate

Al₂(SO₄)₃
*Al³⁺ + SO₄²⁻ → 2 Al³⁺ = +6, 3 SO₄²⁻ = -6.*

37) copper(I) carbonate

Cu₂CO₃
*Cu⁺ + CO₃²⁻ → 2 Cu⁺ needed to balance.*

38) barium oxide

BaO
*Ba²⁺ + O²⁻ → 1:1 ratio.*

39) ammonium sulfite

(NH₄)₂SO₃
*NH₄⁺ + SO₃²⁻ → 2 ammonium ions needed.*

40) silver bromide

AgBr
*Ag⁺ + Br⁻ → 1:1 ratio.*

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## 📝 Summary of Key Rules Used:

- Binary ionic compounds: Metal + nonmetal → name: [Metal] [Nonmetal root + -ide]
- Polyatomic ions: Memorize common ones (e.g., sulfate, nitrate, hydroxide, ammonium).
- Transition metals: Use Roman numerals to indicate charge (e.g., Fe²⁺ = iron(II)).
- Fixed-charge metals (Group 1, 2, Al, Zn, Ag, Cd): No Roman numerals.
- Charge balancing: Total positive charge must equal total negative charge.
- Parentheses: Used when more than one polyatomic ion is needed (e.g., Mg(OH)₂, (NH₄)₂SO₄).

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✔ Final Answer Sheet (Filled In)

Name Column:
1) Sodium carbonate
2) Sodium hydroxide
3) Magnesium bromide
4) Potassium chloride
5) Iron(II) chloride
6) Iron(III) chloride
7) Zinc hydroxide
8) Beryllium sulfate *(note: formula should be BeSO₄)*
9) Chromium(II) fluoride
10) Aluminum sulfide
11) Lead(II) oxide
12) Lithium phosphate
13) Titanium(IV) iodide
14) Cobalt(II) nitride
15) Magnesium phosphide
16) Gallium nitrite
17) Silver sulfite
18) Ammonium hydroxide
19) Aluminum cyanide
20) Beryllium acetate

Formula Column:
21) Na₃P
22) Mg(NO₃)₂
23) PbSO₃
24) Ca₃(PO₄)₂
25) (NH₄)₂SO₄
26) AgCN
27) Al₂S₃
28) BeCl₂
29) Cu₃As
30) Fe₂O₃
31) GaN
32) FeBr₂
33) V₃(PO₄)₅
34) CaO
35) Mg(CH₃COO)₂
36) Al₂(SO₄)₃
37) Cu₂CO₃
38) BaO
39) (NH₄)₂SO₃
40) AgBr

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