Question

covalent bonds worksheet #2
name:
draw the lewis structure for the molecule (and if 4 or more) name it.

1. h + s
2. s + o
3. c + h
4. c + o
5. ammonium sulfide (if 4 or more atoms in the shape)
6. 2 c + 6 h (ethane)
7. 2 h + 2 o (hydrogen peroxide)
8. 2 c + 6 h + 1 o (ethanol)
9. 1 c + 6 h (hexane)
10. 2 c + 2 o + 4 h (acetic acid, vinegar)

Explanation:

Step1: Determine valence electrons for H₂S

Hydrogen (H) has 1 valence electron and sulfur (S) has 6 valence electrons. For H₂S, total valence electrons = 2(1)+6 = 8.

Step2: Place the central atom

Sulfur is the central atom. Connect H atoms to S with single - bonds. Each single - bond uses 2 electrons. So, 4 electrons are used in 2 single - bonds between H and S.

Step3: Distribute remaining electrons

We have 8 - 4 = 4 remaining electrons. Place these 4 electrons as 2 lone - pairs on the sulfur atom. The Lewis structure has S in the center with two single - bonds to H and two lone - pairs on S. Name: Hydrogen sulfide.

For C₂H₆ (ethane)

Step1: Determine valence electrons

Carbon (C) has 4 valence electrons and hydrogen (H) has 1 valence electron. For C₂H₆, total valence electrons = 2(4)+6(1)=14.

Step2: Place the central atoms

The two carbon atoms are bonded to each other with a single - bond. Then, each carbon atom is bonded to 3 hydrogen atoms with single - bonds. Each single - bond uses 2 electrons. In total, there are 7 single - bonds, using 14 electrons. The Lewis structure has two C atoms bonded to each other and each C bonded to 3 H atoms. Name: Ethane.

For Si + O

This is not a molecule in the traditional sense for drawing a Lewis structure as it is just two elements written together. But if we consider silicon monoxide (SiO), Si has 4 valence electrons and O has 6 valence electrons, total = 4 + 6=10. Place Si as the central atom, bond it to O with a double - bond (using 4 electrons), and then place 3 lone - pairs on O and 1 lone - pair on Si. Name: Silicon monoxide.

For C + H

This is not a proper molecule for Lewis - structure drawing. If we consider methane (CH₄), C has 4 valence electrons and H has 1 valence electron, total = 4+4(1) = 8. Place C in the center, bond it to 4 H atoms with single - bonds using all 8 electrons. Name: Methane.

For C + O

If we consider carbon monoxide (CO), C has 4 valence electrons and O has 6 valence electrons, total = 4 + 6=10. Place C and O bonded by a triple - bond (using 6 electrons), and then place 1 lone - pair on C and 1 lone - pair on O. Name: Carbon monoxide.

For elemental sulfur (S₈)

Sulfur has 6 valence electrons. For S₈, total valence electrons = 8×6 = 48. The S atoms are arranged in a ring structure with each S atom bonded to 2 other S atoms. After forming the single - bonds between S atoms (using 16 electrons for 8 single - bonds in the ring), the remaining 48 - 16 = 32 electrons are placed as lone - pairs on each S atom (2 lone - pairs on each S atom). Name: Octasulfur.

For H₂O₂ (hydrogen peroxide)

Hydrogen has 1 valence electron and oxygen has 6 valence electrons. Total valence electrons = 2(1)+2(6)=14. The two O atoms are bonded to each other with a single - bond, and each O atom is bonded to a H atom with a single - bond. After using 6 electrons for 3 single - bonds, we have 14 - 6 = 8 remaining electrons. Place 2 lone - pairs on each O atom. Name: Hydrogen peroxide.

For C₂H₆O (ethanol)

Carbon has 4 valence electrons, hydrogen has 1 valence electron and oxygen has 6 valence electrons. Total valence electrons = 2(4)+6(1)+6 = 20. The two C atoms are bonded to each other. One C is bonded to 3 H atoms and the other C is bonded to 2 H atoms, 1 O atom, and the other C atom. The O atom is also bonded to a H atom. After using 14 electrons for 7 single - bonds, we have 20 - 14 = 6 remaining electrons. Place 3 lone - pairs on O. Name: Ethanol.

For C₆H₆ (benzene)

Carbon has 4 valence electrons and hydrogen has 1 valence electron. Total valence electrons = 6(4)+6(1)=30. The 6 C atoms form a ring. Each C atom is bonded to 2 other C atoms and 1 H atom. There are 3 double - bonds and 6 single - bonds in the resonance structure of benzene. After using 30 electrons in these bonds, there are no remaining electrons. Name: Benzene.

For C₂H₄O₂ (acetic acid, vinegar)

Carbon has 4 valence electrons, hydrogen has 1 valence electron and oxygen has 6 valence electrons. Total valence electrons = 2(4)+4(1)+2(6)=24. One C atom is part of a methyl group (CH₃) and the other C is part of a carboxyl group (COOH). The C in the carboxyl group is double - bonded to one O and single - bonded to another O which is also single - bonded to a H. After using 24 electrons in bonds and lone - pairs (2 lone - pairs on the double - bonded O and 3 lone - pairs on the single - bonded O in the carboxyl group), the structure is complete. Name: Acetic acid.

Answer:

The Lewis structures and names for the given substances (or substances assumed from the given elements) are as described above for each case.