An ion X3+ is obtained from an element X (atomic mass 27 and atomic number…
2023
An ion X3+ is obtained from an element X (atomic mass 27 and atomic number 13). The number of protons, electrons and neutrons in X3+ is respectively :
Answer: D. 13, 10 and 14 — In a neutral atom, the atomic number (Z) equals the number of protons, which also equals the number of electrons; the mass number (A) equals the total of…
- A.
14, 13 and 10
- B.
10, 13 and 14
- C.
13, 13 and 10
- D.
13, 10 and 14
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Correct answer: D
In a neutral atom, the atomic number (Z) equals the number of protons, which also equals the number of electrons; the mass number (A) equals the total of protons and neutrons, so neutrons = A − Z. When the atom loses electrons to form a positive ion Xⁿ⁺, only the electron count decreases by n; the proton and neutron counts stay fixed by the atom's identity.
Applying this to element X (atomic number 13, atomic mass 27) and its ion X3+:
Protons = atomic number Z = 13 (protons never change when an ion forms).
Neutrons = mass number − atomic number = 27 − 13 = 14 (also fixed, independent of ionisation).
The 3+ charge means the atom has lost 3 electrons, so electrons = Z − 3 = 13 − 3 = 10.
So protons, electrons and neutrons are 13, 10 and 14 respectively.
Check: protons + neutrons = 13 + 14 = 27, matching the given mass number; and protons − electrons = 13 − 10 = 3, matching the ion's +3 charge — both confirm the values.