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KCET2011ChemistryThermodynamics (C)

Generally, the first ionisation energy increases along a period. But there are some exceptions. The one which is not an exception is

Options

  1. ABe and B
  2. BNa and Mg
  3. CMg and Al
  4. DN and O

Correct answer

B. Na and Mg

Step-by-step solution

First ionisation energy of Mg is more than that of Na . It is not an exception.

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