NDA2026General AbilityGeneral ScienceActual
If x is the number of electrons and y is the number of nucleons present in ³²₁₆ S ²⁻ , then which one of the following is correct?
Options
- Ax = 14 and y = 32
- Bx = 16 and y = 30
- Cx = 18 and y = 32
- Dx = 18 and y = 30
Correct answer
C. x = 18 and y = 32
Step-by-step solution
The given species is ³²₁₆ S ²⁻ . The atomic number Z of sulfur is 16 , which represents the number of protons. Since the species has a charge of -2 , it has gained 2 electrons. Therefore, the number of electrons x = 16 + 2 = 18 . The mass number A is 32 . The number of nucleons is the sum of protons and neutrons, which is equal to the mass number. Therefore, the number of nucleons y = 32 . Thus, x = 18 and y = 32 .