Question

chemistry students are learning about lewis structures. their instructor asks them to draw lewis structures for carbon dioxide using both electron dots and bonds to show bonding relationships. determine which lewis structures are correct and mark their roman numeral below.
i
ii
iii
iv

Explanation:

Step1: Count valence electrons

Carbon has 4 valence electrons, and each oxygen has 6 valence electrons. For \(CO_2\), total valence electrons \(=4 + 2\times6=16\).

Step2: Check octet rule

• Structure I: Carbon has 6 electrons (violates octet rule as it needs 8).
• Structure II: Total electrons \(=4 + 2\times6=16\). Carbon has 8 electrons (two double - bonds), and each oxygen has 8 electrons.
• Structure III: Carbon has 6 electrons (violates octet rule as it needs 8).
• Structure IV: Carbon has 8 electrons (two double - bonds), and each oxygen has 8 electrons. But in \(CO_2\), carbon forms double - bonds with oxygen (not triple - bonds as in some incorrect interpretations). The correct bonding is two double - bonds. Structure II has the correct electron distribution and bond type (double - bonds) to satisfy the octet rule and valence electron count.

Answer:

II