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प्रश्न
Discuss and compare the trend in ionisation enthalpy of the elements of group1 with those of group17 elements.
उत्तर
As we move across the periodic table the ionization energy increases because of the increase in the effective nuclear charge and decrease of the shielding effect as more and more electrons get added in the same orbital. Thus group 1 has lower ionization enthalpy compared to that of group 17 and also group 1 by losing one electron it will acquire the nearest noble gas electronic configuration which also contributes towards its lower ionization enthalpy.
Important Concepts Discussed in the Classification of Elements and Periodicity in Properties:
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Modern periodic law and the present form of the periodic table
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Nomenclature of elements with atomic numbers > 100 and why do we need to classify elements?
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Genesis of periodic classification
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Electronic configurations of elements and the periodic table
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Groupwise electronic configurations
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Electronic configurations and types of elements: s–, p–, d–, f– BLOCKS
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The s – block elements
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The p – block elements
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The d block elements
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The f block elements (inner-transition elements)
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Metals, non-metals, and metalloids
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Periodic trends in properties of elements
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Trends in physical properties
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Atomic radius
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Ionic radius
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Ionization enthalpy
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Electron gain enthalpy
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Electronegativity
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Periodic trends in chemical properties
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Periodicity of valence or oxidation states
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Anomalous properties of second-period elements
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Periodic trends and chemical reactivity
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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 O has lower ΔiH than N and F?
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?
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?
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
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 ______.
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)
The decreasing order of the second ionization potential of K, Ca and Ba is ______.
