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:

Step1: Calculate valence electrons for HCN

• H has 1 valence electron, C has 4 valence electrons, N has 5 valence electrons.
• Total valence electrons: \(1 + 4+5=10\).
• In the given Lewis structure \(H - C\equiv N\), the number of valence electrons is \(2 + 6+2 = 10\) (single bond has 2 electrons, triple bond has 6 electrons, and lone pairs).
• Check octet rule: H has 2 electrons (duet, which is stable for H), C has \(4 + 6=8\) electrons (satisfies octet), N has \(2+6 = 8\) electrons (satisfies octet).

Step2: Calculate valence electrons for \(O - C - O\)

• Each O has 6 valence electrons, C has 4 valence electrons.
• Total valence electrons: \(6\times2 + 4=16\).
• In the given Lewis structure (single - bonded \(O - C - O\) with lone pairs), the number of valence electrons is \(2\times6+2 + 2=16\) (each single bond has 2 electrons, and lone pairs). But C has only \(4 + 2+2 = 8\) electrons (octet), but the structure should have double bonds (\(O = C = O\)) for a more stable structure. However, in terms of octet rule, C has 8 electrons (from two single bonds and two lone pairs) and each O has \(6 + 2=8\) electrons (from one single bond and three lone pairs). But the more stable form has double bonds. But if we just consider octet (8 - electron rule for C and O), it satisfies the octet rule. Wait, no: C in \(O - C - O\) (single - bonded) has \(4\) (from its own) \(+ 2\) (from two single bonds) \(=6\) electrons (violates octet). The correct structure is \(O = C = O\) where C has \(4+4 = 8\) electrons (two double bonds) and each O has \(6 + 2=8\) electrons (one double bond and two lone pairs).

Step3: Calculate valence electrons for \(NCl_3\)

• Each Cl has 7 valence electrons, N has 5 valence electrons.
• Total valence electrons: \(7\times3+5 = 26\).
• In the given Lewis structure (\(:Cl - N - Cl:\) with a \(Cl\) above \(N\) and lone pairs), the number of valence electrons is \(3\times6+2\times3+2=26\) (each single bond has 2 electrons, and lone pairs).
• Check octet rule: N has \(5+3 = 8\) electrons (three single bonds and one lone pair), each Cl has \(7 + 1=8\) electrons (one single bond and three lone pairs).

Answer:

• For \(H - C\equiv N\): Yes.
• For \(:O - C - O:\): No, it has the right number of valence electrons but doesn't satisfy the octet rule. The symbols of the problem atoms are: C.
• For \(:Cl - N - Cl:\) (with \(Cl\) above \(N\)): Yes.