Let’s solve this step by step for each element: Oxygen, Argon, and Beryllium.
We’ll use the information given in the Bohr model diagrams and the periodic table data (atomic number and atomic mass) to find:
- Atomic Number
- Atomic Mass
- Number of Protons
- Number of Electrons
- Number of Neutrons
Remember these key rules:
→ Atomic Number = Number of Protons = Number of Electrons (in a neutral atom)
→ Number of Neutrons = Atomic Mass (rounded to nearest whole number) – Atomic Number
---
1. Oxygen
From the diagram:
- The nucleus shows “8+” → that means 8 protons.
- The electron shells show 2 electrons in first shell, 6 in second → total 8 electrons.
- Periodic box says: Atomic Number = 8, Atomic Mass = 16.00
So:
- Atomic Number = 8
- Atomic Mass = 16 (we round 16.00 to 16)
- Number of Protons = 8
- Number of Electrons = 8
- Number of Neutrons = 16 – 8 = 8
✔ Check: 8 protons + 8 neutrons = mass number 16 → matches!
---
2. Argon
From the diagram:
- Nucleus shows “18+” → 18 protons.
- Electron shells: 2 + 8 + 8 = 18 electrons.
- Periodic box: Atomic Number = 18, Atomic Mass = 39.95 → round to 40
So:
- Atomic Number = 18
- Atomic Mass = 40
- Number of Protons = 18
- Number of Electrons = 18
- Number of Neutrons = 40 – 18 = 22
✔ Check: 18 protons + 22 neutrons = 40 → matches rounded atomic mass!
---
3. Beryllium
From the diagram:
- Nucleus shows “4+” → 4 protons.
- Electron shells: 2 + 2 = 4 electrons.
- Periodic box: Atomic Number = 4, Atomic Mass = 9.017 → round to 9
So:
- Atomic Number = 4
- Atomic Mass = 9
- Number of Protons = 4
- Number of Electrons = 4
- Number of Neutrons = 9 – 4 = 5
✔ Check: 4 protons + 5 neutrons = 9 → matches rounded atomic mass!
---
Final Answer:
Oxygen
- Atomic Number: 8
- Atomic Mass: 16
- Number of Protons: 8
- Number of Electrons: 8
- Number of Neutrons: 8
Argon
- Atomic Number: 18
- Atomic Mass: 40
- Number of Protons: 18
- Number of Electrons: 18
- Number of Neutrons: 22
Beryllium
- Atomic Number: 4
- Atomic Mass: 9
- Number of Protons: 4
- Number of Electrons: 4
- Number of Neutrons: 5
Parent Tip: Review the logic above to help your child master the concept of bohr model practice worksheets.
