Trend of electronic polarizability in noble gases As one moves to heavier rare gases (e.g., Ne → Ar → Kr → Xe), how does the electronic polarizability of the atoms change?

Electronics and Communication Engineering Materials and Components Difficulty: Easy
Choose an option
  • A
    increases
  • B
    decreases
  • C
    remains the same
  • D
    may increase or decrease without a trend
  • E
    oscillates with atomic number

Answer

Correct Answer: increases

Explanation

Introduction / Context:Electronic polarizability measures how easily an electron cloud is distorted by an electric field. In atomic gases, it depends strongly on the size and binding of the outer electron cloud, informing dielectric design and gas-insulation properties.

Given Data / Assumptions:

  • Consider neutral, isolated noble-gas atoms.
  • Moving down the group increases atomic size and more loosely bound outer electrons.

Concept / Approach:

Larger atoms have more diffuse electron clouds that are more easily distorted. Therefore, polarizability increases approximately monotonically from Ne to Xe. This also explains trends in refractive index and van der Waals interactions strength (dispersion forces increase with polarizability).

Step-by-Step Solution:

Compare atomic size: Ne < Ar < Kr < Xe.Looser binding → greater displacement under field → higher polarizability.Hence, electronic polarizability increases with atomic size.

Verification / Alternative check:

Tabulated atomic polarizabilities and refractivities confirm the monotonic increase across the series.

Why Other Options Are Wrong:

Decrease/constant/oscillatory patterns contradict well-established experimental data and basic electrostatics.

Common Pitfalls:

Confusing periodic trends in different groups or mixing polarizability with ionization energy trends without considering electron-cloud size.

Final Answer:

increases

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