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प्रश्न
Define ionisation enthalpy. Discuss the factors affecting ionisation enthalpy of the elements and its trends in the periodic table.
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उत्तर
The amount of energy required to remove an electron from the outermost shell of an isolated gaseous atom in its ground state is said to be ionisation enthalpy.
The factors that affect ionization enthalpy of the elements are as follows:
a. Effective nuclear charge with its increase the ionization enthalpy also increases
b. Atomic size with its increase the ionization enthalpy decreases
c. The \[\ce{e- - e-}\] repulsion with its increase the ionization enthalpy decreases
d. Whenever there exists half-filled or completely filled orbital than it lead to increase the ionization enthalpy because it leads to give extra stability to the atom due to symmetry
The ionization enthalpy decreases down the group and increases across the period.
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संबंधित प्रश्न
Energy of an electron in the ground state of the hydrogen atom is –2.18 × 10–18 J. Calculate the ionization enthalpy of atomic hydrogen in terms of J mol–1.
Hint: Apply the idea of mole concept to derive the answer.
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?
How would you explain the fact that the first ionization enthalpy of sodium is lower than that of magnesium but its second ionization enthalpy is higher than that of magnesium?
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
Arrange the elements \[\ce{N, P, O}\] and \[\ce{S}\] in the order of increasing first ionisation enthalpy. Give reason for the arrangement assigned.
Explain the following:
Ionisation enthalpy decrease in a group from top to bottom?
Assertion (A): Generally, ionisation enthalpy increases from left to right in a period.
Reason (R): When successive electrons are added to the orbitals in the same principal quantum level, the shielding effect of inner core of electrons does not increase very much to compensate for the increased attraction of the electron to the nucleus.
In general, the property (magnitudes only) that shows an opposite trend in comparison to other properties across a period is ______.
Consider the elements Mg, Al, S, P and Si, the correct increasing order of their first ionization enthalpy is ______.
`"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?
