Question

An ion with mass number 56 contains 3 units of positive charge and 30.4% more neutrons than electrons. Assign the symbol to this ion.

Answer 1

Let the number of electrons present in ion A3+ be x.
∴ Number of neutrons in it = x + 30.4% of x
= 1.304 x Since the ion is tripositive,
⇒ Number of electrons in neutral atom = x + 3
∴ Number of protons in neutral atom = x + 3
Given the mass number of the ion = 56
∴ (x + 3) + (1.304x) = 56
x = $\frac{53}{2.304}$
x = 23
∴ Number of protons = x + 3 = 23 + 3 = 26
∴ The symbol of the ion $_{26}^{56}\textrm{Fe}$3+.