1. Tardigrade
  2. Question
  3. Chemistry
  4. The first (ΔiH1) and the second (ΔiH2) ionization enthalpies (in kj mol-1 ) and the (ΔegH) electron gain enthalpy (in kj mol-1) of a few elements are given below: Elements ΔiH1 ΔiH2 ΔegH I 520 7300 -60 II 419 3051 -48 III 1681 3374 -328 IV 1008 1846 -295 V 2372 5251 +48 Which of the following is least reactive element?

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Q. The first $(\Delta_iH_1)$ and the second $(\Delta_iH_2)$ ionization enthalpies (in $kj \,mol^{-1} )$ and the $(\Delta_{eg}H)$ electron gain enthalpy (in $kj \,mol^{-1})$ of a few elements are given below:
Elements $\Delta_iH_1$ $\Delta_iH_2$ $\Delta_{eg}H$
I 520 7300 -60
II 419 3051 -48
III 1681 3374 -328
IV 1008 1846 -295
V 2372 5251 +48

Which of the following is least reactive element?

Classification of Elements and Periodicity in Properties

Solution:

The element V has highest first ionisation enthalpy and positive electron gain enthalpy. Hence it is least reactive and is a member of inert gases.