Question

decide whether these proposed lewis structures are reasonable.

proposed lewis structure

is the proposed lewis structure reasonable?

yes.

no, it has the wrong number of valence electrons.

the correct number is:

no, it has the right number of valence electrons but doesnt satisfy the octet rule.

the symbols of the problem atoms are:*

yes.

no, it has the wrong number of valence electrons.

the correct number is:

no, it has the right number of valence electrons but doesnt satisfy the octet rule.

the symbols of the problem atoms are:*

yes.

no, it has the wrong number of valence electrons.

the correct number is:

no, it has the right number of valence electrons but doesnt satisfy the octet rule.

the symbols of the problem atoms are:*

• if two or more atoms of the same element dont satisfy the octet rule, just enter the chemical symbol as many times as necessary. for example, if two oxygen atoms dont satisfy the octet rule, enter \o,o\.

Explanation:

First Lewis structure (\(H - C - C - H\))

Step1: Calculate the number of valence electrons

• Hydrogen (\(H\)) has \(1\) valence electron. There are \(2\) \(H\) atoms, so \(2\times1 = 2\) valence electrons from \(H\).
• Carbon (\(C\)) has \(4\) valence electrons. There are \(2\) \(C\) atoms, so \(2\times4=8\) valence electrons from \(C\).
• Total valence electrons \(=2 + 8=10\).
• In the proposed structure, each \(C\) has \(6\) non - bonding electrons (three lone pairs) and \(2\) bonding electrons (one single bond). Each \(H\) has \(2\) bonding electrons. The total number of valence electrons in the proposed structure: For \(C\) atoms, \(2\times(6 + 2)=16\) (counting non - bonding and bonding electrons for \(C\)), and for \(H\) atoms \(2\times2 = 4\). Total \(16+4 = 20\) (wrong).
• The correct number of valence electrons for \(C_2H_2\) (assuming it's \(C_2H_2\)): \(C_2H_2\) has \(2\times4+2\times1=10\) valence electrons.
• Check the octet rule: Each \(C\) in the proposed structure has \(6\) non - bonding electrons and \(2\) bonding electrons (\(6 + 2=8\), octet satisfied for \(C\)), but the electron count is wrong.

Second Lewis structure (\([H - O - H]^+\))

Step1: Calculate the number of valence electrons

• Hydrogen (\(H\)) has \(1\) valence electron. There are \(2\) \(H\) atoms, so \(2\times1 = 2\) valence electrons from \(H\).
• Oxygen (\(O\)) has \(6\) valence electrons.
• The ion is \([H_2O]^+\), so total valence electrons \(=2 + 6-1=7\) (subtract \(1\) because of the \(+1\) charge).
• In the proposed structure: Each \(H\) has \(2\) bonding electrons. The \(O\) has \(2\) non - bonding electrons and \(2\) bonding electrons (two single bonds). Total valence electrons: \(2\times2+2 + 2=8\) (wrong).
• Check the octet rule: \(O\) has \(2\) non - bonding electrons and \(2\) bonding electrons (\(2+2 = 4\), does not satisfy the octet rule).

Third Lewis structure (\(N - N\))

Step1: Calculate the number of valence electrons

• Nitrogen (\(N\)) has \(5\) valence electrons. There are \(2\) \(N\) atoms, so \(2\times5 = 10\) valence electrons.
• In the proposed structure: Each \(N\) has \(6\) non - bonding electrons and \(2\) bonding electrons. Total valence electrons \(=2\times(6 + 2)=16\) (wrong).
• Check the octet rule: Each \(N\) has \(6\) non - bonding electrons and \(2\) bonding electrons (\(6+2 = 8\), octet satisfied for \(N\)), but the electron count is wrong.

Answer:

• For \(H - C - C - H\): No, it has the wrong number of valence electrons. The correct number is \(10\).
• For \([H - O - H]^+\): No, it has the wrong number of valence electrons. The correct number is \(7\).
• For \(N - N\): No, it has the wrong number of valence electrons. The correct number is \(10\).