Naming Ionic Compounds Practice Worksheet | Science 9th Grade - Free Printable

Let's solve this Naming Ionic Compounds Practice Worksheet step by step.

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Part 1: Name the following ionic compounds

We'll name each compound based on the rules for naming ionic compounds:
- For metals with fixed charges (like Group 1, 2, and Al, Zn, Ag), just use the metal name + anion name.
- For transition metals with variable charges (e.g., Fe, Cr, Sn, Pb), include the charge in Roman numerals in parentheses.
- Polyatomic ions have specific names (e.g., NO₃⁻ = nitrate, SO₄²⁻ = sulfate, etc.).

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1) NH₄Cl
- NH₄⁺ is the ammonium ion (a polyatomic cation).
- Cl⁻ is chloride.
- Name: Ammonium chloride

2) Fe(NO₃)₃
- Fe is iron. Since it has a variable charge, we need to determine its oxidation state.
- NO₃⁻ has a -1 charge; three of them → total -3.
- So Fe must be +3.
- Name: Iron(III) nitrate

3) TiBr₃
- Ti is titanium, variable charge.
- Br⁻ is bromide, so three Br⁻ = -3 total → Ti is +3.
- Name: Titanium(III) bromide

4) Cu₃P
- Cu is copper (variable charge).
- P is phosphide (P³⁻).
- Three Cu atoms balance one P³⁻ → each Cu must be +1.
- Name: Copper(I) phosphide

5) SnSe₂
- Sn is tin (variable charge).
- Se²⁻ is selenide; two of them = -4.
- So Sn must be +4.
- Name: Tin(IV) selenide

6) GaAs
- Ga is gallium (fixed charge: +3), As is arsenide (As³⁻).
- This is a binary ionic compound.
- Name: Gallium arsenide

7) Pb(SO₄)₂
- Pb is lead (variable charge).
- SO₄²⁻ is sulfate; two of them = -4 → Pb must be +4.
- Name: Lead(IV) sulfate

8) Be(HCO₃)₂
- Be²⁺ is beryllium (fixed charge).
- HCO₃⁻ is bicarbonate (or hydrogen carbonate).
- Name: Beryllium bicarbonate

9) Mn₂(SO₃)₃
- Mn is manganese (variable charge).
- SO₃²⁻ is sulfite; three of them = -6.
- Two Mn atoms → each Mn is +3.
- Name: Manganese(III) sulfite

10) Al(CN)₃
- Al³⁺ is aluminum (fixed charge).
- CN⁻ is cyanide.
- Name: Aluminum cyanide

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Part 2: Write the formulas for the following compounds

Now we write chemical formulas using charges and balancing.

11) Chromium(VI) phosphate
- Cr⁶⁺ (chromium with +6 charge)
- PO₄³⁻ (phosphate)
- Balance: Cr⁶⁺ and PO₄³⁻ → lowest common multiple of 6 and 3 is 6
- 1 Cr⁶⁺ needs 2 PO₄³⁻ (2 × -3 = -6)
- Formula: Cr(PO₄)₂

12) Vanadium(IV) carbonate
- V⁴⁺
- CO₃²⁻
- Balance: 2 V⁴⁺ = +8, 4 CO₃²⁻ = -8 → 2 V and 4 CO₃
- Formula: V₂(CO₃)₄ → simplified as V₂(CO₃)₄ or V₂(CO₃)₄ (no simplification needed)

Wait — better to reduce subscripts if possible? But V₂(CO₃)₄ is correct. Alternatively, check charge balance:

- V⁴⁺ × 2 = +8
- CO₃²⁻ × 4 = -8 → balanced.
- Formula: V₂(CO₃)₄

But usually written as V₂(CO₃)₄, but sometimes simplified? No, it’s already simplest whole number ratio.

✔ Answer: V₂(CO₃)₄

13) Tin(II) nitrite
- Sn²⁺
- NO₂⁻ (nitrite)
- 1 Sn²⁺ and 2 NO₂⁻ → Sn(NO₂)₂
- Formula: Sn(NO₂)₂

14) Cobalt(III) oxide
- Co³⁺
- O²⁻
- Balance: 2 Co³⁺ = +6, 3 O²⁻ = -6 → Co₂O₃
- Formula: Co₂O₃

15) Titanium(II) acetate
- Ti²⁺
- C₂H₃O₂⁻ (acetate)
- Ti²⁺ and 2 acetate → Ti(C₂H₃O₂)₂
- Formula: Ti(CH₃COO)₂ or Ti(C₂H₃O₂)₂ → Ti(C₂H₃O₂)₂

16) Vanadium(V) sulfide
- V⁵⁺
- S²⁻
- Balance: 2 V⁵⁺ = +10, 5 S²⁻ = -10 → V₂S₅
- Formula: V₂S₅

17) Chromium(III) hydroxide
- Cr³⁺
- OH⁻
- 1 Cr³⁺ and 3 OH⁻ → Cr(OH)₃
- Formula: Cr(OH)₃

18) Lithium iodide
- Li⁺
- I⁻
- LiI
- Formula: LiI

19) Lead(II) nitride
- Pb²⁺
- N³⁻ (nitride)
- Balance: 3 Pb²⁺ = +6, 2 N³⁻ = -6 → Pb₃N₂
- Formula: Pb₃N₂

20) Silver bromide
- Ag⁺ (silver always +1)
- Br⁻
- AgBr
- Formula: AgBr

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✔ Final Answers:

#### Part 1: Naming
1) Ammonium chloride
2) Iron(III) nitrate
3) Titanium(III) bromide
4) Copper(I) phosphide
5) Tin(IV) selenide
6) Gallium arsenide
7) Lead(IV) sulfate
8) Beryllium bicarbonate
9) Manganese(III) sulfite
10) Aluminum cyanide

#### Part 2: Formulas
11) Cr(PO₄)₂
12) V₂(CO₃)₄
13) Sn(NO₂)₂
14) Co₂O₃
15) Ti(C₂H₃O₂)₂
16) V₂S₅
17) Cr(OH)₃
18) LiI
19) Pb₃N₂
20) AgBr

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🔍 Explanation Summary:

- Fixed charge metals (e.g., Al, Ag, Na, Ca): Just name the metal + anion.
- Variable charge metals (transition metals): Use Roman numerals to indicate oxidation state.
- Polyatomic ions: Memorize common ones like NO₃⁻ (nitrate), SO₄²⁻ (sulfate), HCO₃⁻ (bicarbonate), CN⁻ (cyanide), OH⁻ (hydroxide), etc.
- When writing formulas: balance total positive and negative charges using subscripts.

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