Question

lewis structure for covalent compounds (remember octet 8)
practice problems

1. $\ce{f_{2}}$

element	valence electrons	octet 😀
total

lewis structure for $\ce{f_{2}}$:

1. $\ce{co_{2}}$

element	valence electrons	octet 😀
total

lewis structure for $\ce{co_{2}}$:

Explanation:

Problem 1: \( \boldsymbol{F_2} \)

Step 1: Determine Valence Electrons for Fluorine

Fluorine (F) is in group 17, so it has 7 valence electrons. Since there are two F atoms in \( F_2 \):

• First F atom: Valence electrons = 7, Octet needed = 8 (to satisfy octet rule)
• Second F atom: Valence electrons = 7, Octet needed = 8

Step 2: Calculate Total Valence Electrons and Octet

• Total valence electrons: \( 7 + 7 = 14 \)
• Total octet needed: \( 8 + 8 = 16 \) (but we use the bonding to share electrons, so the shared pair counts for both)

Filling the Table:

Element	Valence Electrons	Octet
F	7	8
Total	\( 7 + 7 = 14 \)	\( 8 + 8 = 16 \)

Lewis Structure for \( \boldsymbol{F_2} \)

• Each F atom contributes 7 valence electrons. They share a pair of electrons (a single bond), so the Lewis structure is: \( \text{F} - \text{F} \), with 3 lone pairs on each F (since \( 7 - 1 = 6 \) non - bonding electrons, which form 3 lone pairs).

Problem 2: \( \boldsymbol{CO_2} \)

Step 1: Determine Valence Electrons for Each Element

• Carbon (C) is in group 14, so it has 4 valence electrons. Octet needed = 8.
• Oxygen (O) is in group 16, so each O has 6 valence electrons. There are 2 O atoms, and each O needs 8 electrons for octet.

Step 2: Calculate Total Valence Electrons and Octet

• Total valence electrons: \( 4+(6\times2)=4 + 12 = 16 \)
• Total octet needed: \( 8+(8\times2)=8 + 16 = 24 \)

Filling the Table:

Element	Valence Electrons	Octet
O	6	8
O	6	8
Total	\( 4+6 + 6=16 \)	\( 8 + 8+8 = 24 \)

Lewis Structure for \( \boldsymbol{CO_2} \)

• Carbon is the central atom. It forms double bonds with each O atom. The valence electrons: C has 4, each O has 6. The Lewis structure is \( \text{O}=\text{C}=\text{O} \). Each O has 2 lone pairs (since \( 6 - 2 = 4 \) non - bonding electrons, forming 2 lone pairs) and C has no lone pairs (as it uses all 4 electrons in double bonds to satisfy the octet).

Final Answers (Table Fills and Lewis Structures)

For \( \boldsymbol{F_2} \) Table:

Element	Valence Electrons	Octet
F	7	8
Total	14	16

Lewis Structure: \( \text{F} - \text{F} \) (with 3 lone pairs on each F)

For \( \boldsymbol{CO_2} \) Table:

Element	Valence Electrons	Octet
O	6	8
O	6	8
Total	16	24

Lewis Structure: \( \text{O}=\text{C}=\text{O} \) (with 2 lone pairs on each O)

Answer:

Problem 1: \( \boldsymbol{F_2} \)

Step 1: Determine Valence Electrons for Fluorine

Fluorine (F) is in group 17, so it has 7 valence electrons. Since there are two F atoms in \( F_2 \):

• First F atom: Valence electrons = 7, Octet needed = 8 (to satisfy octet rule)
• Second F atom: Valence electrons = 7, Octet needed = 8

Step 2: Calculate Total Valence Electrons and Octet

• Total valence electrons: \( 7 + 7 = 14 \)
• Total octet needed: \( 8 + 8 = 16 \) (but we use the bonding to share electrons, so the shared pair counts for both)

Filling the Table:

Element	Valence Electrons	Octet
F	7	8
Total	\( 7 + 7 = 14 \)	\( 8 + 8 = 16 \)

Lewis Structure for \( \boldsymbol{F_2} \)

• Each F atom contributes 7 valence electrons. They share a pair of electrons (a single bond), so the Lewis structure is: \( \text{F} - \text{F} \), with 3 lone pairs on each F (since \( 7 - 1 = 6 \) non - bonding electrons, which form 3 lone pairs).

Problem 2: \( \boldsymbol{CO_2} \)

Step 1: Determine Valence Electrons for Each Element

• Carbon (C) is in group 14, so it has 4 valence electrons. Octet needed = 8.
• Oxygen (O) is in group 16, so each O has 6 valence electrons. There are 2 O atoms, and each O needs 8 electrons for octet.

Step 2: Calculate Total Valence Electrons and Octet

• Total valence electrons: \( 4+(6\times2)=4 + 12 = 16 \)
• Total octet needed: \( 8+(8\times2)=8 + 16 = 24 \)

Filling the Table:

Element	Valence Electrons	Octet
O	6	8
O	6	8
Total	\( 4+6 + 6=16 \)	\( 8 + 8+8 = 24 \)

Lewis Structure for \( \boldsymbol{CO_2} \)

• Carbon is the central atom. It forms double bonds with each O atom. The valence electrons: C has 4, each O has 6. The Lewis structure is \( \text{O}=\text{C}=\text{O} \). Each O has 2 lone pairs (since \( 6 - 2 = 4 \) non - bonding electrons, forming 2 lone pairs) and C has no lone pairs (as it uses all 4 electrons in double bonds to satisfy the octet).

Final Answers (Table Fills and Lewis Structures)

For \( \boldsymbol{F_2} \) Table:

Element	Valence Electrons	Octet
F	7	8
Total	14	16

Lewis Structure: \( \text{F} - \text{F} \) (with 3 lone pairs on each F)

For \( \boldsymbol{CO_2} \) Table:

Element	Valence Electrons	Octet
O	6	8
O	6	8
Total	16	24

Lewis Structure: \( \text{O}=\text{C}=\text{O} \) (with 2 lone pairs on each O)