Chapter Exam

Chapter-9 Atomic Structure — Online MCQ Test

Q: What is the smallest particle of an element that retains its chemical properties?

Answer: B. Atom — An atom is the smallest unit of an element that shows the properties of that element. Molecules are formed when atoms combine.

Q: Which subatomic particle carries a negative charge?

Answer: C. Electron — Electrons are negatively charged particles present outside the nucleus. Protons are positive and neutrons are neutral.

Q: Which statement about atoms is correct?

Answer: B. Atoms are made up of subatomic particles — Atoms are made up of subatomic particles such as protons, neutrons, and electrons. They are not visible to the naked eye.

Q: Two atoms of oxygen combine to form O2. This is an example of

Answer: B. A molecule — O2 is formed by the chemical bonding of two oxygen atoms, so it is a molecule. It is not a single atom or an ion.

SCIENCE · Samacheer Kalvi 9th · Tamil Nadu State Board

Practice Chapter-9 Atomic Structure with a free chapter-wise online MCQ test for Tamil Nadu State Board Samacheer Kalvi 9th SCIENCE. This chapter covers: Description Explains atoms molecules subatomic particles and atomic models Keywords Atom Electron Proton Neutron Molecule. AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter-9 Atomic Structure — Important Questions & Answers (FAQ)

Frequently asked questions from Tamil Nadu State Board Samacheer Kalvi 9th SCIENCE — Chapter-9 Atomic Structure, with answers and explanations. These are sample questions; the exam has its own separate question set.

What is the smallest particle of an element that retains its chemical properties?

A. Molecule
B. Atom ✓
C. Compound
D. Ion

Answer: B. Atom
An atom is the smallest unit of an element that shows the properties of that element. Molecules are formed when atoms combine.

Which subatomic particle carries a negative charge?

A. Proton
B. Neutron
C. Electron ✓
D. Nucleus

Answer: C. Electron
Electrons are negatively charged particles present outside the nucleus. Protons are positive and neutrons are neutral.

Which statement about atoms is correct?

A. Atoms can be seen clearly with the naked eye
B. Atoms are made up of subatomic particles ✓
C. Atoms have only electrons and no nucleus
D. Atoms are larger than molecules

Answer: B. Atoms are made up of subatomic particles
Atoms are made up of subatomic particles such as protons, neutrons, and electrons. They are not visible to the naked eye.

Two atoms of oxygen combine to form O2. This is an example of

A. An atom
B. A molecule ✓
C. A nucleus
D. An ion

Answer: B. A molecule
O2 is formed by the chemical bonding of two oxygen atoms, so it is a molecule. It is not a single atom or an ion.

Which option correctly identifies the charged particle and its role in an atom?

A. Proton — negative charge, found outside nucleus
B. Neutron — positive charge, found in nucleus
C. Electron — negative charge, found outside nucleus ✓
D. Electron — neutral charge, found in nucleus

Answer: C. Electron — negative charge, found outside nucleus
Electrons are negatively charged and are located outside the nucleus. Protons are positive and neutrons are neutral, both found in the nucleus.