Atoms and Molecules (9 Science)
Atoms are the smallest units of elements that retain chemical properties, while molecules are combinations of atoms. Understanding atomic structure and che
TL;DR: Atoms are the smallest units of elements that retain chemical properties, while molecules are combinations of atoms. Understanding atomic structure an…
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Atoms are the smallest units of elements that retain chemical properties, while molecules are combinations of atoms. Understanding atomic structure and che
Atoms and Molecules MCQs with Answers & Explanations
Q1. Who proposed the Dalton's atomic theory?
- Rutherford
- John Dalton ✓ (correct)
- Thomson
- Bohr
Q2. The mass number of an atom is equal to:
- Number of protons
- Number of electrons
- Number of protons + neutrons ✓ (correct)
- Number of electrons + neutrons
Q3. Which of the following is the correct electronic configuration of Oxygen (O)?
- 2, 4
- 2, 6 ✓ (correct)
- 2, 8
- 8, 2
Q4. The molecular mass of CO2 is approximately:
- 28
- 32
- 44 ✓ (correct)
- 64
Q5. An ion with a positive charge is called:
- Anion
- Cation ✓ (correct)
- Radical
- Atom
Q6. The atomic mass unit is defined as:
- 1/12 of carbon-12 mass ✓ (correct)
- Mass of proton
- Mass of electron
- 1/16 of oxygen mass
Q7. The formula for common salt is:
- Na2Cl
- NaCl ✓ (correct)
- Na2Cl2
- NaCl2
Q8. Which of the following is a diatomic molecule?
- O3
- P4
- H2 ✓ (correct)
- S8
Q9. The valency of oxygen in most compounds is:
- 1
- 2 ✓ (correct)
- 3
- 4
Q10. The molar mass of H2SO4 is approximately:
- 96
- 98 ✓ (correct)
- 100
- 102
Frequently Asked Questions
What is the difference between atoms and molecules?
An atom is the smallest unit of an element, while a molecule is a combination of atoms bonded together.
How is the atomic mass of an element determined?
The atomic mass is the weighted average of the masses of all naturally occurring isotopes of that element.
More 9 Science MCQs
- Light Reflection and Refraction
- Electricity
- Acids Bases and Salts
- Life Processes
- Carbon and its Compounds
- Metals and Non-metals
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