Question

What does an atom and an ion of the isotope of sodium ${}_{11}^{22}Na$ both contain?

• A. $11$ electrons
• B. $12$ neutrons
• C. $23$ protons
• D. $23$ neutrons

Answer 1

Answer: (B)

$12$ neutrons

i) Na has mass number of 23 and atomic number 11 which means it contains 23-11=12 neutrons ${(}_{23}^{11}Na)$.
ii) But for ${}_{22}^{11}Na$ which is isotope of sodium it will have 11 protons and 12 neutrons.
iii) Similarly the ion of sodium also has 12 neutrons.