Unit Chemical Bonding Covalent Bonding Wksh 3 Answer Key - Fill ... - Free Printable

Let's solve each question from the worksheet step by step and explain the solutions clearly.

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1. What is the difference between a molecular formula, structural formula, and an electron dot formula? Give an example of each.

#### Answer:

- Molecular Formula:
This shows the actual number of atoms of each element in a molecule. It does not show how the atoms are connected.
Example: H₂O – This means two hydrogen atoms and one oxygen atom are present in a water molecule.

- Structural Formula:
This shows how the atoms are bonded together (the arrangement and connections). It includes lines to represent covalent bonds.
Example: For H₂O, the structural formula would be:
```
H
|
O
|
H
```
(This shows that each hydrogen is bonded to the oxygen.)

- Electron Dot Formula (Lewis Structure):
This shows the valence electrons as dots around the atomic symbols and indicates bonding through shared pairs of electrons.
Example: For H₂O, the electron dot formula is:
```
H
..
O
..
H
```
Or more accurately:
```
H : O : H
..
```
The two lone pairs on oxygen are shown as dots.

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2. What is the difference between single, double, and triple covalent bonds? How many shared electrons are in each?

#### Answer:

- Single Covalent Bond:
One pair of electrons is shared between two atoms.
→ 2 shared electrons
Example: H–H (in H₂)

- Double Covalent Bond:
Two pairs of electrons are shared between two atoms.
→ 4 shared electrons
Example: O=O (in O₂)

- Triple Covalent Bond:
Three pairs of electrons are shared between two atoms.
→ 6 shared electrons
Example: N≡N (in N₂)

> Summary Table:
| Bond Type | Shared Electron Pairs | Total Shared Electrons |
|------------------|------------------------|-------------------------|
| Single | 1 | 2 |
| Double | 2 | 4 |
| Triple | 3 | 6 |

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3. Draw the electron dot and structural formulas for the following molecules.

We'll go through each substance:

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#### a) Cl₂ (Chlorine gas)

- Rough copy (word): Chlorine molecule — two chlorine atoms bonded together.
- Electron dot formula (Lewis structure):
```
:Cl : :Cl:
```
Each Cl has 7 valence electrons. They share one pair to complete their octets.

More properly:
```
:Cl - Cl:
```
With three lone pairs on each Cl.

Final Lewis structure:
```
.. ..
:Cl - Cl:
.. ..
```

- Structural formula:
Cl–Cl
(A single bond between two chlorine atoms)

---

#### b) H₂S (Hydrogen sulfide)

- Rough copy (word): Sulfur bonded to two hydrogen atoms.
- Electron dot formula:
- Sulfur has 6 valence electrons; each H has 1.
- Sulfur shares one electron with each H, forming two single bonds.
- Remaining 4 electrons on sulfur form two lone pairs.

Lewis structure:
```
H
|
:S:
|
H
```
Or written as:
```
H : S : H
..
```
But with two lone pairs on sulfur.

Correctly:
```
H
|
.. ..
S
.. ..
|
H
```
Or better:
```
H ..
| |
:S:
| |
H ..
```
Actually, standard notation:
```
H
|
.. ..
S
.. ..
|
H
```

Final electron dot:
```
H : S : H
..
```
With two lone pairs (four dots) on sulfur.

- Structural formula:
```
H
|
S
|
H
```
or simply: H–S–H

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#### c) BrF (Bromine monofluoride)

- Rough copy (word): Bromine bonded to fluorine.
- Electron dot formula:
- Br has 7 valence electrons, F has 7.
- They share one pair → single bond.
- Each atom gets 8 electrons (octet).

Lewis structure:
```
:Br - F:
```
Each has three lone pairs.

More detailed:
```
.. ..
:Br - F:
.. ..
```

So:
```
.. ..
:Br - F:
.. ..
```

- Structural formula:
Br–F

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✔ Final Answers Summary:

#### Question 1:
- Molecular Formula: H₂O
- Structural Formula: H–O–H
- Electron Dot:
```
H : O : H
..
```

#### Question 2:
- Single bond: 2 shared electrons
- Double bond: 4 shared electrons
- Triple bond: 6 shared electrons

#### Question 3:

| Substance | Electron Dot Formula | Structural Formula |
|----------|-----------------------|--------------------|
| a) Cl₂ | `:Cl - Cl:` with three lone pairs on each Cl | Cl–Cl |
| b) H₂S | `H : S : H` with two lone pairs on S | H–S–H |
| c) BrF | `:Br - F:` with three lone pairs on each atom | Br–F |

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✔ All answers are now complete and explained clearly! Let me know if you'd like this formatted into a printable version.