According to molecular theory, the species among the following that does not exist is:
1. \(\text {He}_{2}^{+} \) 2. \(\text {He}_{2}^{-}\)
3. \(\text {Be}_{2}\) 4. \(\text O_{2}^{2 -}\)
Subtopic:  M.O.T |
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Match List-I (Molecules) with List-II (Bond order),
and mark the appropriate choice

List-I (Molecule)  List-II (Bond order)

(a) Ne 

(b) N2  

(c) F2  

(d) O2  

(i) 1

(ii) 2

(iii) 0

(iv) 3

Choose the correct match from the options given below :

1. (a) (iii), (b)  (iv), (c) (i), (d) (ii)

2. (a) (i), (b) (ii), (c) (iii), (d) (iv)

3. (a) (ii), (b) (i), (c) (iv), (d) (iii)

4. (a) (iv), (b) (iii), (c) (ii), (d) (i)

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Of the species, NO , NO+, NO2+ and NO , the one with minimum bond strength is: 

1.  NO2+

2.  NO+

3.  NO 

4.  NO

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The diamagnetic species that has the shortest bond length among the following is-


1. N22-

2. O2

3. C22-

4. O22-

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Among the following, the molecule expected to be stabilized by anion formation is : C2, O2, NO, F2

1. NO
2. O2
3. C2
4. F2

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During the change of O2 to O2-, the incoming electron that goes to the orbital is:

1. \(\sigma _{2pz}^{*}\) 2. π2py
3. \(\sigma _{2pz}\) 4. π*2px
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According to molecular orbital theory, which of the following molecules is not expected to be stable?

1. \(\mathrm{He}_2^{2+}\) 2.  \(\mathrm{He}_2^{+}\)
3. \(\mathrm{H}_2^{-}\) 4.  \(\mathrm{H}_2^{2-}\)
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Arrange the species \(\mathrm{Li}_2\) , \(\mathrm{Li}_2^{-}\) , and \(\mathrm{Li}_2^{+}\)  in order of increasing stability:

1. Li2<Li2<Li2+

2. \(\mathrm{Li}_2^{-}\) = \(\mathrm{Li}_2^{+}\) = \(\mathrm{Li}_2\)

3. Li2<Li2+<Li2

4. Li2<Li2+<Li2

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The molecules/ions that do not contain unpaired electrons among the following is:

1. O22-

2. B2

3. N2+

4. O2

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Species among the following that experience an increase in bond strength upon the removal of an electron are:

(a) B2 
(b) NO 
(c) N2 
(d) O2 
(e) C2 

1. b,d 
2. a,b,d 
3. b,e 
4. b,c
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