Neco Model Questions Vol1 2020 Physics Question 20

Practice objective / multiple choice question 20 from the 2020 Neco Model Questions Vol1 Physics examination.

Neco Model Questions Vol1 2020 Physics Objective / Multiple Choice Hard Difficulty
Question 20 NECO_MODEL_QUESTIONS_VOL1 • 2020 • PHYSICS • objective

A hydrogen‑like ion emits a photon when an electron drops from the \(n = 5\) level to the \(n = 2\) level. The wavelength of this photon is measured to be \(109\ \text{nm}\). (a) Identify the atomic number \(Z\) of the ion. (b) Using this \(Z\), calculate the wavelength of the photon emitted when the electron subsequently drops from \(n = 2\) to \(n = 1\). (c) Find the total energy released in the two‑step transition in kilojoules per mole of ions. (d) Express this total energy as a percentage of the ion's ionisation energy from the ground state.

Answer Options

A. Z=2; λ(2→1)=32.1 nm; total energy≈5.30×10³ kJ mol⁻¹; ≈98 % of the ionisation energy.
B. Z=3; λ(2→1)=28.2 nm; total energy≈4.80×10³ kJ mol⁻¹; ≈90 % of the ionisation energy.
C. Z=1; λ(2→1)=121.6 nm; total energy≈2.18×10³ kJ mol⁻¹; ≈42 % of the ionisation energy.
Correct Answer D. Z=2; λ(2→1)=30.4 nm; total energy≈5.05×10³ kJ mol⁻¹; ≈96 % of the ionisation energy.
Correct Answer
D
Correct Option:
Z=2; λ(2→1)=30.4 nm; total energy≈5.05×10³ kJ mol⁻¹; ≈96 % of the ionisation energy.

About This Question

This is Neco Model Questions Vol1 2020 Physics Question 20. It is one of the objective questions from the 2020 Neco Model Questions Vol1 Physics examination.

Difficulty level: Hard .

View More Neco Model Questions Vol1 2020 Physics Questions More Neco Model Questions Vol1 Practice Questions Back to Questions

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows
Chat with Support