Atomic structure diagrams of selected elements with labeled symbols and electron orbitals.

Let’s solve this step by step.

We are given Bohr model diagrams (circles with dots in the center) for different elements. Each diagram shows electron shells — the circles represent energy levels, and we need to figure out how many electrons go in each shell based on the element’s atomic number.

The key rule:
- The first shell (closest to nucleus) holds up to 2 electrons.
- The second shell holds up to 8 electrons.
- The third shell also holds up to 8 (for these early elements).

We’ll use the periodic table to find the atomic number (number of protons = number of electrons in a neutral atom), then fill the shells from inside out.

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Sodium (Na)
Atomic number = 11 → 11 electrons
Shell 1: 2 electrons
Shell 2: 8 electrons
Shell 3: 1 electron (because 2 + 8 = 10, so 11 - 10 = 1 left)
→ So the diagram should have 3 shells: innermost has 2, middle has 8, outer has 1. But wait — looking at the image, Sodium is shown with 3 concentric circles and one dot in the center? That doesn’t match. Actually, let me re-read.

Wait — I think I misread the task. Looking again: the user provided an image with labels like “Sodium (Na) _____” above a diagram. The blank is probably for writing the electron configuration or number of valence electrons? Or maybe matching the correct diagram?

Actually, looking more carefully — there are six labeled elements, each with a blank line, and below them are three full diagrams and part of three more. It seems like the student is supposed to match each element to its correct Bohr model diagram.

But since the image isn't fully visible (only top row of labels and partial bottom row of diagrams), perhaps the task is to write the electron configuration for each element based on their position.

Alternatively — maybe the blanks are for writing the number of valence electrons? Let’s assume that, because it’s common in such worksheets.

Valence electrons = electrons in the outermost shell.

Let’s calculate for each:

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Sodium (Na) – Atomic number 11
Electron config: 2, 8, 1 → Valence electrons = 1

Aluminum (Al) – Atomic number 13
Config: 2, 8, 3 → Valence electrons = 3

Carbon (C) – Atomic number 6
Config: 2, 4 → Valence electrons = 4

Silicon (Si) – Atomic number 14
Config: 2, 8, 4 → Valence electrons = 4

Oxygen (O) – Atomic number 8
Config: 2, 6 → Valence electrons = 6

Chlorine (Cl) – Atomic number 17
Config: 2, 8, 7 → Valence electrons = 7

This makes sense — these are standard values taught in middle/high school chemistry.

So the blanks are likely for writing the number of valence electrons.

Let me double-check:

- Na: group 1 → 1 valence electron ✔
- Al: group 13 → 3 valence electrons ✔
- C: group 14 → 4 valence electrons ✔
- Si: group 14 → 4 valence electrons ✔
- O: group 16 → 6 valence electrons ✔
- Cl: group 17 → 7 valence electrons ✔

Perfect.

Final Answer:
Sodium (Na) 1
Aluminum (Al) 3
Carbon (C) 4
Silicon (Si) 4
Oxygen (O) 6
Chlorine (Cl) 7