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The first (${{\vartriangle }_{i}}{{H}_{1}}$) and the second (${{\vartriangle }_{i}}{{H}_{2}}$) ionization enthalpies (in kj ${{mol}^{-1}}$) and the (${{\vartriangle }_{eg}}{{H}_{1}}$) electron gain enthalpy (in kj ${{mol}^{-1}}$) of a few elements are giv
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1
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1731
|
August 10, 2016
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Calculate the energy required to convery all atoms of magnesium to magnesium ions present in 24 mg of magnesium vapours. I${{E}_{1}}$ and I${{E}_{2}}$ of Mg are 737.76 and 1450.73 kj ${{mol}^{-1}}$ respectively
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0
|
3490
|
August 10, 2016
|
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Explain why chlorine has higher electron affinity than fluorine
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0
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3791
|
August 10, 2016
|
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Explain the term 'valency' of an element. How does it vary in a period and in a group in the periodic table?
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0
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3574
|
August 10, 2016
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What are various factors due to which ionisation enthalpy of the main group elements tends to decrease down a group?
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0
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4128
|
August 10, 2016
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Predict the formula of the binary compound formed by the combination of the following pairs of elements :
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1
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754
|
August 10, 2016
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The increasing order of reactivity among group elements is Li < Na < Rb < Cs whereas that among group 17 elements is F > Cl > Br > I. Explain
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0
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1381
|
August 10, 2016
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Would you expect the second electron gain enthalpy of O as positive, more negative or less negative than the first ? Justify your answer
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0
|
1229
|
August 10, 2016
|
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Which of the following pairs of elements would have a more negative electron gain enthalpy ? (i) O or F, (ii) F or Cl
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0
|
912
|
August 10, 2016
|
|
How will you explain the fact that first ionisation enthalpy of sodium is lower than that of magnesium but its second ionisation enthalpy is higher than that of magnesium?
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0
|
2452
|
August 10, 2016
|
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Among the second period elements, the actual ionization enthalpies are in the order
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1
|
4020
|
August 10, 2016
|
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Energy of an electron in the ground state of the hydrogen atom is - 2-18 x ${{10}^{-18}}$
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1
|
2807
|
August 10, 2016
|
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What is the significance of the terms 'isolated gaseous atom' and 'ground state' while defining ionisation enthalpy and electron gain enthalpy?
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0
|
13764
|
August 10, 2016
|
|
Consider the following species :
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1
|
570
|
August 10, 2016
|
|
How does atomic radius vary in a period and in a group ? How do you explain the variation?
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0
|
2159
|
August 10, 2016
|
|
What does atomic radius and ionic radius mean to you?
|
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0
|
2457
|
August 10, 2016
|
|
Which one of the following statement is incorrect in relation to ionization enthalpy?
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1
|
1701
|
August 10, 2016
|
|
Anything that influences the valence electrons will affect the chemistry of the element Which one of the following factors does not affect the valence shell?
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1
|
1974
|
August 10, 2016
|
|
The size of isoelectronic species—${{F}^{-}}$. Ne and Na+ is affected by :
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1
|
666
|
August 10, 2016
|
|
Which of the following statements related to the modern periodic table is incorrect?
|
|
1
|
1095
|
August 10, 2016
|
|
Predict the formulae of the stable binary compounds that would be formed by the combination of the following pairs of elements
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|
1
|
2558
|
August 10, 2016
|
|
Which of the following elements has most positive electron gain enthalpy?
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|
1
|
2950
|
August 10, 2016
|
|
What would be the IUPAC name and symbol for the element with atomic number 120?
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0
|
3461
|
August 10, 2016
|
|
Why electron affinities of Be and Mg are positive?
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|
0
|
1587
|
August 10, 2016
|
|
Give four examples of species which are iso electronic with $C{{a}^{2+}}$
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0
|
634
|
August 10, 2016
|
|
Why ionisation enthalpy of nitrogen is greater than that of oxygen?
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|
0
|
803
|
August 10, 2016
|
|
Comment on the statement, "The electron gain enthalpy of halogens decrease in the order F > Cl > Br > I."
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0
|
1538
|
August 10, 2016
|
|
Al atom loses electrons successively to form $A{{l}^{+}}$, $A{{l}^{2+}}$, $A{{l}^{3+}}$ ions. Which step will have highest ionisation enthalpy?
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|
0
|
872
|
August 10, 2016
|
|
What is the basic difference between the terms electron gain enthalpy and electronegativity?
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|
0
|
1431
|
August 10, 2016
|
|
Explain the variation of valence in the periodic table
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|
0
|
3297
|
August 10, 2016
|