Free Printable Atomic Structure Worksheets - Free Printable

Let's go through each part of the worksheet step by step and solve the problems.

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1. Label the parts of the atom shown below.

The diagram shows a simplified atomic model with:

- A central nucleus (with protons and neutrons)
- Electrons orbiting in shells (orbits)

Labels:
- The small black dots moving around the center → Electrons
- The central cluster (with both white and black circles) → Nucleus
- The white circles in the nucleus → Neutrons (no charge)
- The black circles in the nucleus → Protons (positive charge)

So, the three lines point to:
1. Electron (outer circle)
2. Nucleus (center cluster)
3. Proton or Neutron — depends on which arrow points to which

But based on standard labeling:
- Arrow pointing to electron: Electron
- Arrow pointing to nucleus: Nucleus
- Arrow pointing to proton or neutron: Likely Proton if it's a black dot in the nucleus

Assuming:
- Top arrow → Electron
- Right arrow → Nucleus
- Bottom arrow → Proton (if black) or Neutron (if white)

Since the question says "label the parts", we need to assign:

✔ Top: Electron
✔ Right: Nucleus
✔ Bottom: Proton (assuming black dot), or Neutron (if white)

But since both are present, and typically the nucleus is labeled as such, and particles inside it are protons and neutrons, we can label accordingly.

So final labels:
- Electron
- Nucleus
- Proton or Neutron — but likely one is proton, one is neutron

However, in most diagrams like this:
- The nucleus is labeled
- One arrow might point to proton, another to neutron

But here, only three lines are drawn. So likely:
- One line → Electron
- One line → Nucleus
- One line → Proton or Neutron

Given that, assume:
- Top: Electron
- Right: Nucleus
- Bottom: Proton (if black) or Neutron (if white)

But since the nucleus contains both, and the bottom arrow points to a particle inside the nucleus, it could be either.

To be safe, let’s say:
- Electron
- Nucleus
- Proton (assuming the black dot represents proton)

> ✔ Answer:
> - Top: Electron
> - Right: Nucleus
> - Bottom: Proton

*(Note: If the bottom is white, it would be Neutron, but typically black = proton, white = neutron)*

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2. Answer the following questions.

a) What part of the atom has no charge?
→ Neutron
✔ Answer: Neutron

b) What part of the atom has a positive charge?
→ Proton
✔ Answer: Proton

c) What part of the atom has a negative charge?
→ Electron
✔ Answer: Electron

d) How many electrons can be held in the first orbital?
→ The first energy level (orbital) can hold up to 2 electrons.
✔ Answer: 2

e) How many electrons can be held in the second orbital?
→ The second energy level can hold up to 8 electrons.
✔ Answer: 8

f) The atomic number represents the number of which particles?
→ Atomic number = number of protons
✔ Answer: Protons

g) The mass number is determined by the sum of the numbers of which particles?
→ Mass number = number of protons + neutrons
✔ Answer: Protons and Neutrons

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3. Identify the atoms from their atomic structures.

We have three diagrams. Let's analyze each.

#### Diagram 1:
- Nucleus: 6 black (protons) + 6 white (neutrons)? Wait — count carefully.
- But actually, the black and white dots represent protons and neutrons.

Let’s count:

##### First Atom (left):
- Protons: 6 black dots in nucleus → 6 protons
- Neutrons: 6 white dots → 6 neutrons
- Electrons: 2 in first shell, 4 in second shell → total 6 electrons
- Atomic number = 6 → Element: Carbon (C)
- Mass number = 6 + 6 = 12 → Carbon-12

✔ Answer: Carbon

##### Second Atom (middle):
- Protons: 8 black dots → 8 protons
- Neutrons: 8 white dots → 8 neutrons
- Electrons: 2 in first shell, 6 in second → total 8 electrons
- Atomic number = 8 → Element: Oxygen (O)
- Mass number = 16 → Oxygen-16

✔ Answer: Oxygen

##### Third Atom (right):
- Protons: 5 black dots → 5 protons
- Neutrons: 5 white dots → 5 neutrons
- Electrons: 2 in first shell, 3 in second → total 5 electrons
- Atomic number = 5 → Element: Boron (B)
- Mass number = 10 → Boron-10

✔ Answer: Boron

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✔ Final Answers:

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1. Label the parts:

- Top: Electron
- Right: Nucleus
- Bottom: Proton (or Neutron, depending on color; assuming black = proton)

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2. Questions:

a) Neutron
b) Proton
c) Electron
d) 2
e) 8
f) Protons
g) Protons and Neutrons

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3. Identify atoms:

- Left: Carbon
- Middle: Oxygen
- Right: Boron

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📌 Summary:

This worksheet tests basic understanding of atomic structure:
- Subatomic particles (protons, neutrons, electrons)
- Charges
- Electron capacity per shell
- Atomic number vs. mass number
- Identifying elements from diagrams

All answers are based on fundamental chemistry principles.

Let me know if you'd like a printable version or explanation for any specific part!