Short Answer TypeWhich of the following elements has more negative electron gain enthalpy?
(i) [Ne] 3s2sp3
(ii) [Ne] 3s23p4
(iii) [Ne] 3s2 3p5
Long Answer TypeWhich of the following pairs of elements would have a more negative electron gain enthalpy?
(i) O or F (ii) F or Cl
(i) O or F. Electron gain enthalpy of F is much more negative than that of O. This is because as we from O to F, the atomic size decreases and nuclear charge increases, thereby increase the attraction of the nucleus for the incoming electron and hence electron gain enthalpy becomes more negative. Moreover gain of one electron by F gives F- ion which has stable inert gas configuration (1s22s2, p6).
(ii) F or Cl: In general, the electron gain enthalpy becomes less negative on moving down the group. But the electron gain enthalpy of chlorine is more negative than that of flourine. This is due to the small size of F atom. Due to its small size, the electron-electron repulsion in the relatively compact 2p-subshell are comparatively larger than those present in the bigger 3p-subshell of Cl. Therefore, chlorine has higher tendency to accept an addition electron than F.
What is the significance of the terms - "isolated gaseous atom' and 'ground state' while defining the ionization enthalpy and electron gain enthalpy?
Short Answer TypeExplain, which of the following pairs of elements would have a more negative electron gain enthalpy:
(i) N or O (ii) O or S
Using the periodic table predicts the formulae of compounds which might be formed by the following pairs of elements:
(a) Silicon and bromine.
(b) Aluminium and sulphur.
The electron gain enthalpy of chlorine is 3.7 eV per atom. How much enthalpy in kJ is released when 1g of chlorine is converted completely of Cl- ion in the gaseous state?
Long Answer TypeShort Answer TypeWrite the electronic configuration of the elements with Z = 9, 11 and 36. Predict the following from the configuration:
(i) Which of them has the large negative value of electron gain enthalpy?
(ii) Which of them has the lowest ionisation enthalpy?
(iii) Which has positive electron gain enthalpy?
Long Answer TypeUse the periodic table to answer the following questions:
(a) Identify an element with five electrons in the outer subshell.
(b) Identify an element that would tend to lose two electrons.
(c) Identify an element that would tend to gain two electrons.
(d) Identify the group having metal, non-metal, liquid as well as gas at the room temperature.
The increasing order of reactivity among group 1 elements is Li < Na < K < Rb is F > CI > Br > I. Explain.
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