ATOMS AND MOLECULES - MCQs

🎯 Knowledge Check

Chemistry — ATOMS AND MOLECULES

50 Questions Class 9 MCQs
1
Who gave the law of conservation of mass?
2
The law of definite proportions was given by:
3
Who proposed the atomic theory?
4
According to Dalton’s atomic theory, atoms of different elements:
5
Which of the following is a triatomic molecule?
6
The smallest particle of an element that can take part in a chemical reaction is called:
7
The symbol of sodium is derived from its Latin name:
8
The formula of water is:
9
The molecular mass of \(\mathrm{CO_2}\) is:
10
Which of the following is a polyatomic ion?
11
The atomic mass unit (amu) is based on:
12
The chemical formula of calcium hydroxide is:
13
Who gave the law of multiple proportions?
14
The number of atoms in one molecule of ammonia \(\mathrm{(NH_3)}\) is:
15
The valency of oxygen is:
16
The chemical formula of sulphuric acid is:
17
Avogadro’s number represents:
18
The molecular formula of glucose is:
19
The ratio of hydrogen to oxygen in water by mass is:
20
The total number of atoms in one molecule of \(\mathrm{CO_2}\) is:
21
The formula of magnesium chloride is:
22
Which of the following is a diatomic molecule?
23
One mole of any substance contains:
24
The molecular mass of \(\mathrm{H_2SO_4}\) is:
25
Which law states that mass can neither be created nor destroyed?
26
The combining capacity of an element is called its:
27
The formula of aluminium oxide is:
28
The relative atomic mass of an element is the ratio of the average mass of one atom to:
29
The molecular formula of methane is:
30
The symbol 'S' represents:
31
Which of the following is a compound?
32
The chemical formula of carbon dioxide is:
33
Which of the following correctly represents a molecule of an element?
34
The atomicity of phosphorus \(\mathrm{(P_4)}\) is:
35
The mass of one mole of water is:
36
The molecular formula of hydrogen peroxide is:
37
The term ‘molecule’ is best defined as:
38
The total number of atoms in one molecule of glucose \(\mathrm{(C_6H_12O_6)}\) is:
39
The atomic mass of oxygen is:
40
The number of moles in 18 g of water is:
41
Which of the following statements is correct according to Dalton’s theory?
42
The formula of ammonium sulphate is:
43
The molecular formula of sulphur dioxide is:
44
The number of atoms in one mole of oxygen gas \(\mathrm{(O_2)}\) is:
45
Which of the following is not a correct chemical formula?
46
Which of the following is a cation?
47
The number of hydrogen atoms in 1 molecule of \(\mathrm{C_2H_6}\) is:
48
The valency of aluminium is:
49
The molecular mass of calcium carbonate \(\mathrm{(CaCO_3)}\) is:
50
Which of the following pairs of elements form a compound in a 1:1 ratio?
Share this Chapter

Found this helpful? Share this chapter with your friends and classmates.

WhatsApp Telegram X / Twitter Facebook LinkedIn

💡 Exam Tip: Share helpful notes with your study group. Teaching others is one of the fastest ways to reinforce your own understanding.

Frequently Asked Questions

An atom is the smallest particle of an element that retains its chemical properties.

A molecule is a group of two or more atoms chemically bonded together.

Dalton’s theory states matter is made of indivisible atoms, identical for each element, combining in fixed ratios.

A chemical formula represents a compound using symbols and shows elements’ proportions.

Atomic mass unit is a standard mass unit equal to 1/12 the mass of one carbon-12 atom.

Atomicity is the number of atoms in a molecule of an element or compound.

A mole is the amount of substance containing Avogadro’s number of particles (6.022 × 10²³).

Mass is neither created nor destroyed during a chemical reaction.

Elements combine in a fixed mass ratio to form a compound.

It is the ratio of the average atomic mass of an element to 1/12 of a carbon-12 atom’s mass.

Avogadro’s number is 6.022 × 10²³, the number of particles in one mole of substance.

An ion is an atom or molecule with a net electric charge due to electron gain or loss.

Atom is a single particle; molecule consists of two or more atoms bonded together.

The symbol for sodium is Na.

Polyatomic ions are ions formed by a group of atoms with an overall charge.

Recent Posts

    --:-- ⏱ Time
    ⚡ Progress 0 / 50 answered

    ATOMS AND MOLECULES – Learning Resources

    Detailed Notes
    True / False
    NCERT Solutions
    Q&A Discussion

    Get in Touch

    Let's Connect

    Questions, feedback, or suggestions?
    We'd love to hear from you.