Question 39 of 43advanced🔧 ApplyNumerical3 marks
The species ²⁷Al, ⁸⁰Br⁻ and ²⁰¹Hg²⁺ have 13, 35 and 80 protons, respectively. How many electrons and neutrons do they have?
(i)
²⁷Al (13 protons): How many electrons and neutrons?
Answer
Electrons: 13, Neutrons: 14
(ii)
⁸⁰Br⁻ (35 protons): How many electrons and neutrons?
Answer
Electrons: 36, Neutrons: 45
(iii)
²⁰¹Hg²⁺ (80 protons): How many electrons and neutrons?
Answer
Electrons: 78, Neutrons: 121
Explanation
For any atomic species, the number of neutrons is calculated by subtracting the atomic number (number of protons) from the mass number (superscript). For electrons, a neutral atom has electrons equal to its protons. If the species carries a negative charge (anion), it has gained electrons; if it carries a positive charge (cation), it has lost electrons.