Free Printable Valence Electrons and Lewis Dot Structure Worksheets - Free Printable

Here is the step-by-step solution to fill in the table.

Step 1: Understand the Columns

* Group Number: This tells us which vertical column on the Periodic Table the element belongs to (using the standard 1–18 numbering).
* Number of Valence Electrons: These are the electrons in the outermost shell. For main group elements, this usually matches the ones digit of the group number (e.g., Group 1 has 1, Group 13 has 3, Group 17 has 7). *Note: Helium is an exception, but it's not on this list.*
* Lewis Structure: We draw the element's symbol and put dots around it to represent the valence electrons. Imagine a square around the letter; place one dot on each side before pairing them up.
* Electrons Gained or Lost: Atoms want a full outer shell (usually 8 electrons, like Noble gases).
* If they have 1, 2, or 3 valence electrons, it is easier to lose them.
* If they have 5, 6, or 7 valence electrons, it is easier to gain enough to reach 8.
* If they have 4, they can go either way (but often share). Hydrogen is special; it only needs 2 total, so it gains/loses 1.

Step 2: Solve for Each Element

1. Hydrogen (H)
* Group: 1
* Valence Electrons: 1
* Lewis Structure: H with 1 dot.
* Gain/Lost: It needs 2 electrons to be full (like Helium). It has 1, so it needs to gain 1. (Note: In many contexts, it can also lose 1 to become H+, but "gaining 1" completes its shell to match the nearest noble gas configuration of He). Let's stick with gain 1 as it fills the orbit.

2. Beryllium (Be)
* Group: 2
* Valence Electrons: 2
* Lewis Structure: Be with 2 dots.
* Gain/Lost: It has 2. To get to 8, it would need to gain 6 (hard). It is easier to lose 2.

3. Boron (B)
* Group: 13
* Valence Electrons: 3
* Lewis Structure: B with 3 dots.
* Gain/Lost: It has 3. Easier to lose 3 than gain 5.

4. Nitrogen (N)
* Group: 15
* Valence Electrons: 5
* Lewis Structure: N with 5 dots (one pair, three singles).
* Gain/Lost: It has 5. Needs 3 more to make 8. So, gain 3.

5. Oxygen (O)
* Group: 16
* Valence Electrons: 6
* Lewis Structure: O with 6 dots (two pairs, two singles).
* Gain/Lost: It has 6. Needs 2 more to make 8. So, gain 2.

6. Chlorine (Cl)
* Group: 17
* Valence Electrons: 7
* Lewis Structure: Cl with 7 dots (three pairs, one single).
* Gain/Lost: It has 7. Needs 1 more to make 8. So, gain 1.

7. Calcium (Ca)
* Group: 2
* Valence Electrons: 2
* Lewis Structure: Ca with 2 dots.
* Gain/Lost: It has 2. Easier to lose 2.

8. Aluminum (Al)
* Group: 13
* Valence Electrons: 3
* Lewis Structure: Al with 3 dots.
* Gain/Lost: It has 3. Easier to lose 3.

9. Bromine (Br)
* Group: 17
* Valence Electrons: 7
* Lewis Structure: Br with 7 dots.
* Gain/Lost: It has 7. Needs 1 more to make 8. So, gain 1.

10. Sulfur (S)
* Group: 16
* Valence Electrons: 6
* Lewis Structure: S with 6 dots.
* Gain/Lost: It has 6. Needs 2 more to make 8. So, gain 2.

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Final Answer:

| Element | Group number | Number of valence electrons | Lewis structure | Number of electrons gained or lost |
| :--- | :---: | :---: | :--- | :--- |
| Hydrogen | 1 | 1 | H with 1 dot | Gain 1 |
| Beryllium | 2 | 2 | Be with 2 dots | Lose 2 |
| Boron | 13 | 3 | B with 3 dots | Lose 3 |
| Nitrogen | 15 | 5 | N with 5 dots | Gain 3 |
| Oxygen | 16 | 6 | O with 6 dots | Gain 2 |
| Chlorine | 17 | 7 | Cl with 7 dots | Gain 1 |
| Calcium | 2 | 2 | Ca with 2 dots | Lose 2 |
| Aluminum | 13 | 3 | Al with 3 dots | Lose 3 |
| Bromine | 17 | 7 | Br with 7 dots | Gain 1 |
| Sulfur | 16 | 6 | S with 6 dots | Gain 2 |