Chapter Exam

Chapter-2 Atomic Structure — Online MCQ Test

Q: Which of the following particles has a positive charge?

Answer: B. Proton — Protons carry a positive charge equal to +1. Electrons are negative, neutrons are neutral, and photons are uncharged particles.

Q: What is the relative mass of a neutron compared to a proton?

Answer: A. Approximately 1 — Neutrons and protons have nearly equal mass (approximately 1 atomic mass unit each). Electrons are much lighter at about 0.0005 amu.

Q: Isotopes of an element have different numbers of which particles?

Answer: C. Neutrons — Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons. This gives them different mass numbers but identical chemical properties.

Q: Which of the following is NOT a subatomic particle?

Answer: D. Atom — An atom is composed of subatomic particles (protons, neutrons, and electrons), but the atom itself is not a subatomic particle—it is the smallest unit of an element.

CHEMISTRY · Grade 10 · IGCSE cambridge

Practice Chapter-2 Atomic Structure with a free chapter-wise online MCQ test for IGCSE cambridge Grade 10 CHEMISTRY. This chapter covers: Protons neutrons and electrons electronic configuration isotopes and the structure of the atom.. AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter-2 Atomic Structure — Important Questions & Answers (FAQ)

Frequently asked questions from IGCSE cambridge Grade 10 CHEMISTRY — Chapter-2 Atomic Structure, with answers and explanations. These are sample questions; the exam has its own separate question set.

Which of the following particles has a positive charge?

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

Answer: B. Proton
Protons carry a positive charge equal to +1. Electrons are negative, neutrons are neutral, and photons are uncharged particles.

What is the relative mass of a neutron compared to a proton?

A. Approximately 1 ✓
B. Approximately 0.5
C. Approximately 2
D. Approximately 0.0005

Answer: A. Approximately 1
Neutrons and protons have nearly equal mass (approximately 1 atomic mass unit each). Electrons are much lighter at about 0.0005 amu.

Isotopes of an element have different numbers of which particles?

A. Protons
B. Electrons
C. Neutrons ✓
D. Both protons and neutrons

Answer: C. Neutrons
Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons. This gives them different mass numbers but identical chemical properties.

Which of the following is NOT a subatomic particle?

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

Answer: D. Atom
An atom is composed of subatomic particles (protons, neutrons, and electrons), but the atom itself is not a subatomic particle—it is the smallest unit of an element.

An element X has three naturally occurring isotopes with mass numbers 24, 25, and 26. All isotopes have 12 protons. Which statement is incorrect?

A. X has an atomic number of 12
B. The three isotopes have different numbers of neutrons
C. The three isotopes have different atomic numbers ✓
D. X is the element magnesium

Answer: C. The three isotopes have different atomic numbers
Isotopes of the same element must have the same atomic number (number of protons). Since all three have 12 protons, they all have atomic number 12. Different atomic numbers would mean different elements, not isotopes.