Free NCERT Solutions, Notes & MCQs for Class 9–12

ATOMS AND MOLECULES - True/False

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Q 01 / 25

Atoms are indivisible and indestructible.

✔ True ✘ False

Q 02 / 25

A molecule of water contains two hydrogen atoms and one oxygen atom.

✔ True ✘ False

Q 03 / 25

Chemical symbols are always represented by one or two letters.

✔ True ✘ False

Q 04 / 25

Oxygen is a monatomic molecule.

✔ True ✘ False

Q 05 / 25

Law of conservation of mass states that mass can be created or destroyed.

✔ True ✘ False

Q 06 / 25

Law of constant proportions is also known as the law of definite proportions.

✔ True ✘ False

Q 07 / 25

Dalton’s atomic theory was the first to propose that atoms combine in simple ratios to form compounds.

✔ True ✘ False

Q 08 / 25

The atomic mass unit (amu) is defined based on hydrogen.

✔ True ✘ False

Q 09 / 25

Sodium's chemical symbol is So.

✔ True ✘ False

Q 10 / 25

HCl represents hydrochloric acid.

✔ True ✘ False

Q 11 / 25

The number of protons and electrons are equal in a neutral atom.

✔ True ✘ False

Q 12 / 25

\(\mathrm{O_2}\) represents a polyatomic molecule.

✔ True ✘ False

Q 13 / 25

One mole of any substance contains Avogadro’s number of particles.

✔ True ✘ False

Q 14 / 25

Gram molecular mass is the mass of one molecule in grams.

✔ True ✘ False

Q 15 / 25

Chemical formula of ammonia is \(\mathrm{NH_3}\).

✔ True ✘ False

Q 16 / 25

Atoms of the same element can have different masses.

✔ True ✘ False

Q 17 / 25

Hydrogen and oxygen combine to form water in a 2:1 mass ratio.

✔ True ✘ False

Q 18 / 25

The symbol for chlorine is Cl.

✔ True ✘ False

Q 19 / 25

All molecules are compounds.

✔ True ✘ False

Q 20 / 25

The valency of hydrogen is one.

✔ True ✘ False

Q 21 / 25

Atoms can exist freely in nature.

✔ True ✘ False

Q 22 / 25

Ions are electrically neutral.

✔ True ✘ False

Q 23 / 25

\(\mathrm{SO_4^{2-} is a polyatomic ion.

✔ True ✘ False

Q 24 / 25

Isotopes have the same atomic number but different mass numbers.

✔ True ✘ False

Q 25 / 25

Law of multiple proportions applies to any two elements combining to form more than one compound.

✔ True ✘ False

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ACADEMIA AETERNUM तमसो मा ज्योतिर्गमय · Est. 2025

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Free NCERT Solutions, Notes & MCQs for Class 9–12 | Academia Aeternum

Free NCERT Solutions, Notes & MCQs for Class 9–12 | Academia Aeternum — Complete Notes & Solutions · academia-aeternum.com

🎓 Class 0 📐 📖 NCERT ✅ Free Access 🏆 CBSE · JEE

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