Advertisements
Advertisements
Question
Nitrogen has positive electron gain enthalpy whereas oxygen has negative. However, oxygen has lower ionisation enthalpy than nitrogen. Explain.
Advertisements
Solution
The outermost electronic configuration of nitrogen is `2s^2 2p_x^1 2p_y^1 2p_z^1`. It is stable because it has exactly half-filled 2p-subshell. Therefore, it has no tendency to accept extra electron and energy has to be supplied to add additional electron. Thus, electron gain enthalpy of nitrogen is slightly positive. On the other hand, the outermost electronic configuration of O is `2s^2 2p_x^2 2p_y^1 2p_z^1`. It has higher positive charge (+8) than nitrogen (+7) and lower atomic size than N. Therefore, it has a tendency to accept an extra electron. Thus, electron gain enthalpy of O is negative. However, oxygen has four electrons in the 2p subshell and can lose one electron to acquire stable half-filled configuration and therefore, it has low ionization enthalpy. Because of stable configuration of N, it cannot readily lose electron and therefore, its ionization enthalpy is higher than that of O.
APPEARS IN
RELATED QUESTIONS
Among the second period elements the actual ionization enthalpies are in the
order Li < B < Be < C < O < N < F < Ne.
Explain why Be has higher ΔiH than B?
Among the second period elements the actual ionization enthalpies are in the
order Li < B < Be < C < O < N < F < Ne.
Explain why O has lower ΔiH than N and F?
What are the various factors due to which the ionization enthalpy of the main group elements tends to decrease down a group?
The first ionization enthalpy values (in kJmol–1) of group 13 elements are:-
| B | Al | Ga | In | Tl |
| 801 | 577 | 579 | 558 | 589 |
How would you explain this deviation from the general trend?
Would you expect the first ionization enthalpies for two isotopes of the same element to be the same or different? Justify your answer.
Which one of the following statements is incorrect in relation to ionization enthalpy?
Those elements impart colour to the flame on heating in it, the atoms of which require low energy for the ionisation (i.e., absorb energy in the visible region of spectrum). The elements of which of the following groups will impart colour to the flame?
(i) 2
(ii) 13
(iii) 1
(iv) 17
Among the elements \[\ce{B, Al, C}\] and \[\ce{Si}\], which element has the highest first ionisation enthalpy?
Explain the deviation in ionisation enthalpy of some elements from the general trend by using the given figure.
Explain the following:
Ionisation enthalpy decrease in a group from top to bottom?
Define ionisation enthalpy. Discuss the factors affecting ionisation enthalpy of the elements and its trends in the periodic table.
Discuss and compare the trend in ionisation enthalpy of the elements of group1 with those of group17 elements.
Consider the elements Mg, Al, S, P and Si, the correct increasing order of their first ionization enthalpy is ______.
For the gaseous reaction, \[\ce{K_{(g)} + F_{(g)} -> K^+_{ (g)} + F^-_{ (g)}}\], ΔH was calculated to be 19 kcal/mol under conditions where the cations and anions were prevented by electrostatic separation from combining with each other. The ionisation energy of K is 4.3 eV. The electron affinity of F is ______. (in eV)
`"A"_0/2` atoms of X(g) are converted into X+(g) by absorbing energy E1. `"A"_0/2` ions of X+(g) are converted into X−(g) with release of energy E2. Hence ionization energy and electron affinity of X(g) are ______.
The decreasing order of the second ionization potential of K, Ca and Ba is ______.
Which of the following atoms has the highest first ionization energy?
