CIE iGCSE Co-Ordinated Science C2.3 Isotopes Exam Style Questions Paper 1
Question
How many neutrons are in one atom of the isotope $_{17}^{35}\textrm{Cl}$ ?
(A) 17
(B) 18
(C) 35
(D 52
▶️Answer/Explanation
Ans: B
Question
The diagrams represent pairs of nuclei of some atoms.
Which pair shows nuclei of different isotopes of the same element?
▶️Answer/Explanation
Ans : B
Question
X and Y are isotopes of the same element.
Which statement about X and Y is correct?
(A) They have the same nucleon number but different numbers of protons.
(B) They have the same number of neutrons but different numbers of electrons.
(C) They have the same atomic number but different numbers of electrons.
(D) They have the same number of protons but different numbers of neutrons.
▶️Answer/Explanation
Ans: D
Question
Which statement about isotopes of the same element is correct?
(A) They have the same number of protons but different number of electrons.
(B) They have the same number of protons but different number of neutrons.
(C) They have the same number of neutrons but different number of electrons.
(D) They have the same number of neutrons but different number of protons.
▶️Answer/Explanation
Ans: B
Question
A beaker contains water that is all at 20 °C.
A convection current is started in the water, as shown in the diagram.
Four points are labelled W, X, Y and Z.
Which two actions can each, on their own, cause this convection current?
(A) cooling the water at W or heating the water at Y
(B) cooling the water at W or heating the water at Z
(C) cooling the water at X or heating the water at Y
(D) cooling the water at X or heating the water at Z
▶️Answer/Explanation
Ans: D
Question
An element has two isotopes.
Which statement about the nuclei of atoms of these isotopes is correct?
(A) They have equal numbers of neutrons but different numbers of electrons.
(B) They have equal numbers of neutrons but different numbers of protons.
(C) They have equal numbers of protons but different numbers of electrons.
(D) They have equal numbers of protons but different numbers of neutrons.
▶️Answer/Explanation
Ans: D
Question
The electronic structures of four isotopes are shown.
Which isotopes have the same chemical properties?
A. 1 and 3
B. 1 and 4
C. 2 and 3
D. 2 and 4
▶️Answer/Explanation
Answer: A. 1 and 3
Explanation: Isotopes of the same element have the same number of protons and electrons, which means they have the same electronic structure and thus the same chemical properties. Therefore, isotopes 1 and 3, which are isotopes of the same element, have the same chemical properties.
Question
One atom of an isotope of fluorine is represented by \( ^{19}_{9}F \). How many neutrons does this atom have?
A. 6
B. 9
C. 10
D. 15
▶️Answer/Explanation
Answer: C. 10
Explanation: The number of neutrons is calculated by subtracting the atomic number (protons) from the mass number. For \( ^{19}_{9}F \), the number of neutrons is \( 19 – 9 = 10 \).
Question
One isotope of oxygen is \( \text{O}^{16}_8 \). Which diagram represents a different isotope of oxygen?
▶️Answer/Explanation
Answer: D. 9 protons, 9 neutrons
Explanation: Isotopes of an element have the same number of protons but different numbers of neutrons. Therefore, the correct answer is D, which has 8 protons (same as oxygen) but 9 neutrons, making it a different isotope.
Question
Which row compares the nucleus and the electronic structure of two isotopes of the same element?
▶️Answer/Explanation
Answer: B
Explanation: Isotopes have the same number of protons and electrons (same electronic structure) but different numbers of neutrons (different nucleus).