Free Printable Atomic Structure Worksheets - Free Printable

Let's go through the Atomic Structure Worksheet step by step and solve each question 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 nucleus has a ________ charge and consists of ________ and ________.

Answer:
The nucleus has a positive charge and consists of protons and neutrons.

✔ Explanation:
- Protons carry a positive charge, neutrons are neutral → overall nucleus is positively charged.
- Both protons and neutrons are located in the nucleus.

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3. Electrons are located in the ________ of an atom and carry ________ charge.

Answer:
Electrons are located in the electron cloud (or shells/orbitals) of an atom and carry a negative charge.

✔ Explanation:
- Electrons move around the nucleus in regions called electron shells or orbitals (electron cloud).
- They have a negative charge of -1.

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4. The number of protons in one atom of an element determines the atom's ________, and the number of electrons determines ________ of an element.

Answer:
The number of protons determines the atom’s atomic number, and the number of electrons determines the chemical behavior (or charge / ionization state).

✔ Explanation:
- Atomic number = number of protons → defines the element.
- Number of electrons affects how the atom interacts chemically; if unequal to protons, it becomes an ion.

> Note: In a neutral atom, number of electrons = number of protons.

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5. The atomic number tells you the number of ________ in one atom of an element. It also tells you the number of ________ in a neutral atom of that element. The atomic number gives the "identity" of an element as well as its location on the Periodic Table. No two different elements will have the same atomic number.

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

✔ Explanation:
- Atomic number = # of protons.
- In a neutral atom, # of electrons = # of protons.
- Each element has a unique atomic number.

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

Use the periodic table:

| Element | Symbol | Number of Protons |
|--------------|--------|--------------------|
| Beryllium | Be | 4 |
| Fluorine | F | 9 |
| Magnesium | Mg | 12 |
| Sulfur | S | 16 |
| Cobalt | Co | 27 |
| Tin | Sn | 50 |
| Arsenic | As | 33 |
| Gold | Au | 79 |

✔ Explanation:
The number of protons = atomic number. Look up each element’s atomic number on the periodic table.

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7. Give the symbol and number of electrons in a neutral atom of:

In a neutral atom, number of electrons = number of protons = atomic number.

| Element | Symbol | Number of Electrons |
|--------------|--------|---------------------|
| Potassium | K | 19 |
| Argon | Ar | 18 |
| Calcium | Ca | 20 |
| Chromium | Cr | 24 |
| Cadmium | Cd | 48 |
| Lead | Pb | 82 |

✔ Explanation:
For example:
- Potassium (K) has atomic number 19 → 19 protons → 19 electrons in neutral atom.

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8. Give the isotope symbol and number of neutrons in one atom of the following elements. Show your calculations.

We use the formula:
Number of neutrons = Mass number – Atomic number

Let’s find the atomic numbers first (from periodic table):

| Element | Mass Number | Atomic Number | Neutrons = Mass – Atomic | Isotope Symbol |
|--------------|-------------|---------------|----------------------------|----------------|
| Cesium | 133 | 55 | 133 – 55 = 78 | \(^{133}_{55}\text{Cs}\) |
| Iron | 54 | 26 | 54 – 26 = 28 | \(^{54}_{26}\text{Fe}\) |
| Ruthenium | 106 | 44 | 106 – 44 = 62 | \(^{106}_{44}\text{Ru}\) |
| Nickel | 58 | 28 | 58 – 28 = 30 | \(^{58}_{28}\text{Ni}\) |
| Polonium | 209 | 84 | 209 – 84 = 125 | \(^{209}_{84}\text{Po}\) |
| Iodine | 135 | 53 | 135 – 53 = 82 | \(^{135}_{53}\text{I}\) |
| Indium | 115 | 49 | 115 – 49 = 66 | \(^{115}_{49}\text{In}\) |
| Phosphorus | 31 | 15 | 31 – 15 = 16 | \(^{31}_{15}\text{P}\) |

✔ Explanation:
- Isotope notation: \(^{A}_{Z}\text{X}\), where:
- A = mass number (protons + neutrons)
- Z = atomic number (protons)
- X = chemical symbol
- Subtract atomic number from mass number to get neutrons.

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✔ Final Answers Summary:

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

#### 2.
Positive, protons, neutrons

#### 3.
Electron cloud, negative

#### 4.
Atomic number, chemical behavior (or charge/ionization)

#### 5.
Protons, electrons, same

#### 6.
- Beryllium: Be, 4
- Fluorine: F, 9
- Magnesium: Mg, 12
- Sulfur: S, 16
- Cobalt: Co, 27
- Tin: Sn, 50
- Arsenic: As, 33
- Gold: Au, 79

#### 7.
- Potassium: K, 19
- Argon: Ar, 18
- Calcium: Ca, 20
- Chromium: Cr, 24
- Cadmium: Cd, 48
- Lead: Pb, 82

#### 8.
| Element | Isotope Symbol | Neutrons |
|--------------|--------------------|----------|
| Cesium | \(^{133}_{55}\text{Cs}\) | 78 |
| Iron | \(^{54}_{26}\text{Fe}\) | 28 |
| Ruthenium | \(^{106}_{44}\text{Ru}\) | 62 |
| Nickel | \(^{58}_{28}\text{Ni}\) | 30 |
| Polonium | \(^{209}_{84}\text{Po}\) | 125 |
| Iodine | \(^{135}_{53}\text{I}\) | 82 |
| Indium | \(^{115}_{49}\text{In}\) | 66 |
| Phosphorus | \(^{31}_{15}\text{P}\) | 16 |

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