(d) An atom of magnesium can be represented by the symbol ²⁴₁₂Mg.
Use numbers to complete these statements about this atom.
(ii) The mass number of this atom is ......................

📝 Detailed explanation

In the standard isotope notation ^A_ZX:
The bottom number Z is the Atomic Number (number of protons).
The top number A is the Mass Number (protons + neutrons).
The mass number of this atom is 24.