ExamBro
ExamBro
KCET · Chemistry · Thermodynamics (C)

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

  1. A \(\mathrm{N}\) and \(\mathrm{O}\)
  2. B \(\mathrm{Na}\) and \(\mathrm{Mg}\)
  3. C \(\mathrm{Mg}\) and \(\mathrm{Al}\)
  4. D Be and B
Verified Solution

Answer & Solution

Correct Answer

(B) \(\mathrm{Na}\) and \(\mathrm{Mg}\)

Step-by-step Solution

Detailed explanation

Na belongs to IA group and Mg belongs to IIA group. On moving form left to right in a period, first ionization energy increases, thus, IE of \(\mathrm{Mg}\) is greater than the IE of Na.
IE order \(\mathrm{Mg}>\mathrm{Na}\)