Parts of an Atom worksheet for educational use, featuring a diagram and labeling exercise.

Let’s solve this step by step.

First, look at the atom diagram in Part A. The center is called the nucleus — it holds protons and neutrons. Around the nucleus are circles with dots — those are electron shells, and the dots on them are electrons.

Now, let’s label each part:

- The red arrow pointing to the very center (where the blue and gray balls are) → that’s the Nucleus.
- The arrows pointing to the small blue balls inside the nucleus → those are Protons (they’re usually shown as positive or colored differently).
- The arrows pointing to the gray balls inside the nucleus → those are Neutrons (neutral, no charge).
- The arrows pointing to the dotted circles around the nucleus → those are Electron Shells (or energy levels).
- The arrows pointing to the little “e⁻” symbols on the shells → those are Electrons.

Wait — looking again at the diagram: there are 3 boxes on the left and 2 on the right. Let’s match them carefully.

Left side (top to bottom):
1. Top box points to an electron on the outer shell → Electron
2. Middle box points to a proton in the nucleus → Proton
3. Bottom box points to a neutron in the nucleus → Neutron

Right side (top to bottom):
1. Top box points to the whole central cluster → Nucleus
2. Bottom box points to one of the circular paths → Electron Shell

That makes sense.

Now Part B: Explain the role of each part.

- Proton: Found in the nucleus. Has a positive charge. Determines what element the atom is (atomic number = number of protons).
- Neutron: Also in the nucleus. No charge (neutral). Helps hold the nucleus together; affects mass but not identity.
- Electron: Orbits outside the nucleus in shells. Negative charge. Involved in bonding and chemical reactions.
- Nucleus: Center of the atom. Contains protons and neutrons. Holds most of the atom’s mass.
- Electron Shells: Paths or regions where electrons move. Different shells hold different numbers of electrons. Outer shell determines how the atom reacts.

Part C: What element does this atom depict?

Count the protons! In the nucleus, we see 3 blue balls (protons). So atomic number = 3 → that’s Lithium.

Double-check: Lithium has 3 protons, and in its neutral state, 3 electrons. Looking at the diagram: 2 electrons in first shell, 1 in second → total 3 electrons. Perfect match.

Final Answer:
Part A Labels (left to right, top to bottom):
Left: Electron, Proton, Neutron
Right: Nucleus, Electron Shell

Part B Roles:
- Proton: Positive particle in nucleus; defines the element.
- Neutron: Neutral particle in nucleus; adds mass, stabilizes nucleus.
- Electron: Negative particle orbiting nucleus; involved in chemistry.
- Nucleus: Central core holding protons and neutrons.
- Electron Shells: Layers where electrons live; determine reactivity.

Part C: Lithium