To name compounds clearly, chemists follow nomenclature rules. The naming of ionic and molecular compounds follows somewhat different procedures. Nomenclature, a set of guidelines for naming things, is crucial in science and many other contexts.

Definition: An ionic compound is a chemical compound made up of ions held together by electrostatic forces known as ionic bonding.

Naming Ionic Compounds Chemistry Questions with Solutions

Q-1: What do you mean by the nomenclature of ionic compounds?

Answer: Nomenclature of ionic compounds is the process of giving different names to chemical compounds so that they can be distinguished as distinct chemicals. For example, KOH is potassium hydroxide and NaCl is sodium chloride.

Q-2: Which of the following is the correct name for Fe(HCO₃)₂?

a) Ferric bicarbonate

b) Iron(II) hydrogen carbonate

c) Iron hydrogen carbonate

d) Iron bicarbonate

Answer: b) Iron(II) hydrogen carbonate

Explanation: Iron can exist in more than one oxidation state, so its oxidation state must be specified in parentheses. Iron(II) hydrogen carbonate is the proper name for it because of this.

Q-3: How can you name ionic compounds with polyatomic cations?

Answer: Two naming conventions exist for polyvalent cations. –

The first method – An ion’s positive charge is denoted by a Roman numeral placed in parentheses after the name of the element and the word ion.

The second method uses two (-ic and -ous) suffixes that are attached to the element name’s stem. The lower of the two cation charges is indicated by the -ous suffix, while the higher is indicated by the -ic suffix.

Q-4: How are binary ionic compounds named when a metal forms multiple cations?

Answer: If an ionic compound’s formula specifies that its metal cation may have more than one possible charge, one must first ascertain the cation’s charge before determining the compound’s correct name.

Take FeCl₂and FeCl₃as examples. Due to the presence of two Cl^– ions in the formula (one charge on each chloride ion), the iron ion in the first compound has a +2 charge. The three Cl^– ions in the second compound’s formula signify the iron ion’s +3 charge. These two compounds are distinct from one another and require distinct names. These charges are written as Roman numerals in parentheses after the metal ion name. Thus, the names are iron(II) chloride and iron(III) chloride, respectively.

Q-5: What is the significance of naming ionic compounds?

Answer: Ionic compounds are named so that they can be easily distinguished as separate chemicals.

Q-6: How are ionic compounds formed?

Answer: Ionic compounds are defined as those held together by ionic bonds. In order to reach their closest configuration as a noble gas, elements can either gain or lose electrons. For the completion of octets, ions are formed (either by gaining or losing electrons), which aids in their stabilisation.

Metals typically lose electrons to complete their octet in a reaction with nonmetals, whereas nonmetals typically gain electrons to complete their octet. Ionic compounds are typically formed during reactions between metals and nonmetals.

Q-7: What does a Roman numeral in parentheses indicate when naming ionic compounds?

a) Number of metal ions

b) Number of nonmetal ions

c) Oxidation state of a metal

c) Oxidation state of a nonmetal

Answer: c) Oxidation state of a metal

Explanation: If a metal can produce ions with various oxidation states, its name is followed by a Roman numeral in parentheses to indicate the oxidation state of the metal.

Q-8:What does the prefix in the name of an ionic compound signify?

a) Number of atoms for each element

b) Number of ions

c) Number of negative charges

d) Number of positive charges

Answer: a) Number of atoms for each element

Explanation: Prefixes are used to specify the number of atoms of each element in a compound’s molecule because molecular compounds can form compounds with different ratios of their constituent elements. Examples include N₂O₄, dinitrogen tetroxide. Here, ‘di’ signifies two nitrogen atoms, and ‘tetra’ represents four oxygen atoms.

Q-9: Fill in the name and empirical formula for each ionic compound.

Cation	Anion	Empirical Formula	Name of the Compound
a) Fe³⁺	S^2-
b) Pb²⁺	IO₃^–
c) Na⁺	HPO₄^–

Answer:

Cation	Anion	Empirical Formula	Name of the Compound
a) Fe³⁺	S^2-	Fe₂S₃	Iron(III) Sulphide
b) Pb²⁺	IO₃^–	Pb(IO₃)₂	Lead(II) Iodate
c) Na⁺	HPO₄^–	Na₂HPO₄	Sodium Hydrogen Phosphate

Q-10: Write the formulas for the following chemical compounds.

a) Manganese(II) phosphate

b) Ammonium oxide

c) Tetrasulphur dinitride

d) Yttrium chlorate

e) Lithium sulphite

Answer:

a) Mn₃(PO₄)₂

b) (NH₄)₂O

c) S₄N₂

d) YClO₃

e) Li₂SO₃

Q-11: Give the name of the following ionic compounds.

a) LiC₂H₃O₂

b) Pb₃N₂

c) CoCO₃

d) Ti(SO₄)₂

e) Ga₂O₃

Answers:

a) Lithium acetate

b) Lead(II) nitride

c) Cobalt(II) carbonate

d) Titanium(IV) sulphate

e) Gallium oxide

Q-12: Complete the following table:

Compound	Name of the Metal Cation	Name of the Nonmetal Anion	Name of the Compound
A) V₂O₅
B) HgCl₂
C) Sr₃(PO₄)₂
C) Ag₂S
D) Mg₃P₂

Answer:

Compound	Name of the Metal Cation	Name of the Nonmetal Anion	Name of the Compound
A) V₂O₅	V⁵⁺	O^2-	Vanadium(V) oxide
B) HgCl₂	Hg²⁺	Cl^–	Mercuric chloride
C) Sr₃(PO₄)₂	Sr²⁺	PO₄^3-	Strontium phosphate
C) Ag₂S	Ag⁺	S^2-	Silver sulphide
D) Mg₃P₂	Mg²⁺	P^3-	Magnesium phosphide

Q-13:Which one of the following anions does not have the suffix “ide”?

a) S^2-

b) P^3-

c) C₂O₄^2-

d) N^3-

Answer: c) C₂O₄^2-

Explanation: Except C₂O₄^2-, all have “ide” as a suffix at their end. C₂O₄^2- is an oxalate ion.

Q-14: Write the formula for the fluoride, sulphide and iodide for the following metal and metal ions.

a) Aluminium

b) Lead(IV)

c) Potassium

Answer:

Metal/Metal Ion	Fluoride	Sulphide	Iodide
a) Aluminium	AlF₃	Al₂S₃	AlI
b) Lead(IV)	PbF₄	PbS₂	PbI₄
c) Potassium	KF	K₂S	KI

Q-15: Match the following:

Name of the Ionic Compound	Use
A) Sodium Hypochlorite	i) Antacid
B) Potassium Phosphate	ii) Added to purified water
C) Magnesium Sulphate	iii) Preservative
D) Magnesium Hydroxide	iv) Food additive
E) Sodium Sulphite	v) Active ingredient in household bleach

Answer: A)-v), B)-iv), C)-ii), D)-i), E)-iii)

Practice Questions on Naming Ionic Compounds

Q-1: Write the name of the following ionic compounds.

a) Al₂(CO₃)₃

b) Mg₃(PO₄)₂

c) CaCO₃

Q-2: Write the name for each of the following ions.

a) Stannous ion

b) Chromic ion

c) Aurous ion

d) Phosphide ion

e) Iodide ion

Q-3: What does the suffix “ous” represent?

a) Lower of the two cation charges

b) Higher of the two cation charges

c) Higher or lower depending on the ion

d) None of the above

Q-4: Write the rules for writing the ionic compounds formula.

Q-5: Write the formulas for the ionic compounds listed below.

a) Chromium(III) Chloride

b) Copper(II) Selenide

c) Titanium(III) Sulphate

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