Free Printable Atomic Structure Worksheets - Free Printable

Let's go through each question on the "Basic Atomic Structure" worksheet and solve them step by step with explanations.

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1. Name the three particles of the atom and their respective charges.

| Particle | Charge type | Charge |
|--------------|-------------|---------------|
| Proton | Positive | +1 |
| Neutron | Neutral | 0 |
| Electron | Negative | -1 |

Explanation:
- Protons are positively charged particles found in the nucleus.
- Neutrons have no charge (neutral) and are also in the nucleus.
- Electrons are negatively charged and orbit the nucleus.

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2. The number of protons in one atom of an element determines the atom’s ________ and the number of ________ determines the charge of the element.

Answer:
The number of protons in one atom of an element determines the atom’s atomic number and the number of electrons determines the charge of the element.

Explanation:
- The atomic number is defined as the number of protons in the nucleus.
- The charge of an atom depends on the balance between protons (+) and electrons (–). If there are more protons than electrons, the atom is positively charged (cation); if more electrons, it's negatively charged (anion).

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3. The ____________ tells you the number of protons in one atom of an element. It also tells you the number of ________ in a neutral atom of that element.

Answer:
The atomic number tells you the number of protons in one atom of an element. It also tells you the number of electrons in a neutral atom of that element.

Explanation:
In a neutral atom, the number of protons equals the number of electrons, so the atomic number gives both values.

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4. No two different elements will have the _______ atomic number.

Answer:
No two different elements will have the same atomic number.

Explanation:
Each element has a unique atomic number (number of protons), which defines the element. For example, hydrogen has atomic number 1, helium has 2, etc.

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5. The ____________ of an element is the average mass of an element’s naturally occurring atom or ________ taking into account the mass of each isotope.

Answer:
The atomic mass of an element is the average mass of an element’s naturally occurring atom or isotopes taking into account the mass of each isotope.

Explanation:
Atomic mass is a weighted average based on the masses and natural abundances of all isotopes of an element.

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6. The ____________ of an element is the total number of protons and ________ in the nucleus of the atom.

Answer:
The mass number of an element is the total number of protons and neutrons in the nucleus of the atom.

Explanation:
Mass number = protons + neutrons. This is not the same as atomic mass (which is averaged over isotopes), but refers to a specific atom.

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7. Give the symbol and the number of protons in one atom of:

| Element | Symbol | Number of Protons |
|-----------|--------|-------------------|
| Lithium | Li | 3 |
| Bromine | Br | 35 |
| Iron | Fe | 26 |
| Copper | Cu | 29 |
| Oxygen | O | 8 |
| Mercury | Hg | 80 |
| Krypton | Kr | 36 |
| Helium | He | 2 |

Explanation:
The number of protons is equal to the atomic number, which can be found on the periodic table.

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8. Give the symbol and the number of electrons in one atom of:

> Note: This assumes neutral atoms, where number of electrons = number of protons.

| Element | Symbol | Number of Electrons |
|-------------|--------|---------------------|
| Uranium | U | 92 |
| Carbon | C | 6 |
| Boron | B | 5 |
| Fluorine | F | 9 |
| Chlorine | Cl | 17 |
| Europium | Eu | 63 |
| Barium | Ba | 56 |
| Bismuth | Bi | 83 |

Explanation:
Again, for neutral atoms, the number of electrons equals the number of protons (atomic number).

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✔ Final Answer Summary:

1.
| Particle | Charge Type | Charge |
|------------|-------------|--------|
| Proton | Positive | +1 |
| Neutron | Neutral | 0 |
| Electron | Negative | -1 |

2. atomic number, electrons
3. atomic number, electrons
4. same
5. atomic mass, isotopes
6. mass number, neutrons

7.
- Lithium: Li, 3
- Bromine: Br, 35
- Iron: Fe, 26
- Copper: Cu, 29
- Oxygen: O, 8
- Mercury: Hg, 80
- Krypton: Kr, 36
- Helium: He, 2

8.
- Uranium: U, 92
- Carbon: C, 6
- Boron: B, 5
- Fluorine: F, 9
- Chlorine: Cl, 17
- Europium: Eu, 63
- Barium: Ba, 56
- Bismuth: Bi, 83

Let me know if you'd like this formatted as a printable answer key!