CIE iGCSE Co-Ordinated Science P5.1 The nucleus Exam Style Questions Paper 1
▶️ Answer/Explanation
The mass number A counts all nucleons (protons + neutrons), while the atomic number Z counts only protons.
Subtracting A − Z removes the proton count, leaving only the neutrons.
Therefore \(A – Z\) is equal to the number of neutrons in the nucleus.
✅ Answer: (B)
Subtracting A − Z removes the proton count, leaving only the neutrons.
Therefore \(A – Z\) is equal to the number of neutrons in the nucleus.
✅ Answer: (B)
▶️ Answer/Explanation
The proton number (bottom number) is given as 38.
The mass number (top number) equals protons plus neutrons, so \(38 + 52 = 90\).
Nuclide notation places the mass number above the proton number, giving \(^{90}_{38}\textrm{Sr}\).
✅ Answer: (B)
The mass number (top number) equals protons plus neutrons, so \(38 + 52 = 90\).
Nuclide notation places the mass number above the proton number, giving \(^{90}_{38}\textrm{Sr}\).
✅ Answer: (B)
▶️ Answer/Explanation
In nuclide notation \( ^{A}_{Z}X \), the bottom number Z is the proton number and the top number A is the nucleon (mass) number.
Here \( Z = 1 \), so there is 1 proton, and \( A = 3 \), so the total number of protons and neutrons is 3.
The number of neutrons is \( A – Z = 3 – 1 = 2 \), giving
Here \( Z = 1 \), so there is 1 proton, and \( A = 3 \), so the total number of protons and neutrons is 3.
The number of neutrons is \( A – Z = 3 – 1 = 2 \), giving
▶️ Answer/Explanation
The proton number (bottom number) is the number of protons, which is 79 for gold.
The nucleon number (top number) is the total number of protons and neutrons: \( 79 + 118 = 197 \).
So the correct nuclide symbol is \( ^{197}_{79}\text{Au} \), with 197 on top and 79 on the bottom.
✅ Answer: (D)
The nucleon number (top number) is the total number of protons and neutrons: \( 79 + 118 = 197 \).
So the correct nuclide symbol is \( ^{197}_{79}\text{Au} \), with 197 on top and 79 on the bottom.
✅ Answer: (D)
▶️ Answer/Explanation
Isotopes of the same element must have identical proton numbers (same number of protons in each nucleus of the pair) but different neutron numbers.
Checking each pair of diagrams for equal proton counts but differing neutron counts identifies pair B as the correct match.
✅ Answer: (B)
Checking each pair of diagrams for equal proton counts but differing neutron counts identifies pair B as the correct match.
✅ Answer: (B)