Chemistry worksheet for learning valence electrons and Lewis dot structures.

Final Answer:
| Element | Group number | Number of valence electrons | Lewis structure | Number of electrons gained or lost |
|-------------|--------------|-----------------------------|-----------------|------------------------------------|
| Hydrogen | 1 | 1 | H• | loses 1 (to form H⁺) or gains 1 (to form H⁻) — usually shares in covalent bonds |
| Beryllium | 2 | 2 | •Be• | loses 2 (forms Be²⁺) |
| Boron | 13 | 3 | •B• | loses 3 (forms B³⁺), but often shares (covalent) |
| Nitrogen | 15 | 5 | •N: | gains 3 (forms N³⁻) |
| Oxygen | 16 | 6 | :Ö: (or •Ö• with 2 dots on top/bottom) | gains 2 (forms O²⁻) |
| Chlorine | 17 | 7 | :Cl• | gains 1 (forms Cl⁻) |
| Calcium | 2 | 2 | •Ca• | loses 2 (forms Ca²⁺) |
| Aluminum | 13 | 3 | •Al• | loses 3 (forms Al³⁺) |
| Bromine | 17 | 7 | :Br• | gains 1 (forms Br⁻) |
| Sulfur | 16 | 6 | :S: | gains 2 (forms S²⁻) |

Note: For Lewis structures, we show valence electrons as dots around the element symbol. For simplicity and standard school-level answers:
- H: 1 dot → H•
- Be: 2 dots (side by side) → •Be•
- B: 3 dots → •B•
- N: 5 dots (1 pair + 3 singles) → •N: (two dots on one side, one each on three others)
- O: 6 dots (2 pairs + 2 singles) → :Ö: (two pairs and two single dots)
- Cl, Br: 7 dots (3 pairs + 1 single) → :Cl•
- Ca, Al: same as Be and B respectively
- S: like O → :S:

But since the question asks only for the *final answer*, and formatting a full table with hand-drawn Lewis dots isn’t possible in plain text, the cleanest correct final answer is the filled table with group numbers, valence electrons, and electron gain/loss behavior as above.

However, per instruction: only the final correct answer, and it must be concise.

So here is the minimal required final answer in compact form:

Hydrogen: Grp 1, 1 valence e⁻, loses 1 or shares
Beryllium: Grp 2, 2, loses 2
Boron: Grp 13, 3, loses 3
Nitrogen: Grp 15, 5, gains 3
Oxygen: Grp 16, 6, gains 2
Chlorine: Grp 17, 7, gains 1
Calcium: Grp 2, 2, loses 2
Aluminum: Grp 13, 3, loses 3
Bromine: Grp 17, 7, gains 1
Sulfur: Grp 16, 6, gains 2