Question

Assertion :Bond order is defined as one half the difference between number of bonding and antibonding orbitals. Reason: Bond order of $L{i}_2$ is one which means molecule is highly unstable.

• A. Both Assertion and Reason are true and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are true but Reason is not the correct explanation for Assertion
• C. Assertion is true statement but Reason is false.
• D. Both Assertion and Reason are false statements.

Answer 1

The correct option is C Assertion is true statement but Reason is false.

• In molecular orbital theory, bond order is also defined as half the difference between the number of bonding electrons and the number of antibonding electrons.
  
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• The molecule dilithium ($L{i}_2$). The 1s electrons do not take part in the bonding, but the 2s electrons fill the bonding orbital.
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• The molecule $L{i}_2$ is a stable molecule in the gas phase, with a bond order of one.
  
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• Hence option C is correct answer.