Atomic Mass And Number Worksheet PDF Form - FormsPal - Free Printable

To solve this Atomic Mass and Atomic Number Worksheet, you need to understand the relationships between the key atomic properties:

---

🔑 KEY RELATIONSHIPS (for neutral atoms):

1. Atomic Number = Number of Protons
2. Number of Electrons = Number of Protons *(in a neutral atom)*
3. Atomic Mass ≈ Protons + Neutrons → So, Neutrons = Atomic Mass – Atomic Number

> ⚠️ Note: Atomic mass is usually rounded to the nearest whole number for these calculations (since it’s the mass number in most worksheets).

---

We’ll go row by row and fill in the blanks using the periodic table and the above rules.

---

## ✔ SOLUTION — FILLED WORKSHEET

| Name of Element | Symbol | Atomic Number | Atomic Mass | Protons | Neutrons | Electrons |
|-----------------|--------|---------------|-------------|---------|----------|-----------|
| Copper | Cu | 29 | 64 | 29 | 35 | 29 |
| Tin | Sn | 50 | 119 | 50 | 69 | 50 |
| Iodine | I | 53 | 127 | 53 | 74 | 53 |
| Uranium | U | 92 | 238 | 92 | 146 | 92 |
| Potassium | K | 19 | 39 | 19 | 20 | 19 |
| Lithium | Li | 3 | 7 | 3 | 4 | 3 |
| Oxygen | O | 8 | 16 | 8 | 8 | 8 |
| Gold | Au | 79 | 197 | 79 | 118 | 79 |
| Sulfur | S | 16 | 32 | 16 | 16 | 16 |
| Silver | Ag | 47 | 108 | 47 | 61 | 47 |
| Chromium | Cr | 24 | 52 | 24 | 28 | 24 |
| Cobalt | Co | 27 | 59 | 27 | 32 | 27 |
| Nickel | Ni | 28 | 58 | 28 | 30 | 28 |
| Zinc | Zn | 30 | 65 | 30 | 35 | 30 |
| Aluminum | Al | 13 | 27 | 13 | 14 | 13 |
| Mercury | Hg | 80 | 201 | 80 | 121 | 80 |
| Platinum | Pt | 78 | 195 | 78 | 117 | 78 |
| Iron | Fe | 26 | 56 | 26 | 30 | 26 |
| Hydrogen | H | 1 | 1 | 1 | 0 | 1 |
| Helium | He | 2 | 4 | 2 | 2 | 2 |
| Beryllium | Be | 4 | 9 | 4 | 5 | 4 |
| Magnesium | Mg | 12 | 24 | 12 | 12 | 12 |
| Carbon | C | 6 | 12 | 6 | 6 | 6 |
| Silicon | Si | 14 | 28 | 14 | 14 | 14 |
| Chlorine | Cl | 17 | 35 | 17 | 18 | 17 |
| Bismuth | Bi | 83 | 209 | 83 | 126 | 83 |
| Boron | B | 5 | 11 | 5 | 6 | 5 |
| Calcium | Ca | 20 | 40 | 20 | 20 | 20 |
| Manganese | Mn | 25 | 55 | 25 | 30 | 25 |
| Lead | Pb | 82 | 207 | 82 | 125 | 82 |
| Sodium | Na | 11 | 23 | 11 | 12 | 11 |
| Fluorine | F | 9 | 19 | 9 | 10 | 9 |
| Phosphorus | P | 15 | 31 | 15 | 16 | 15 |

---

## 📌 EXPLANATION OF HOW EACH WAS FILLED:

Let’s take a few examples to show the logic:

---

Example 1: Copper (given: protons=29, neutrons=35, electrons=29)

- Atomic Number = Protons = 29
- Symbol = Cu (from periodic table)
- Atomic Mass ≈ Protons + Neutrons = 29 + 35 = 64

---

Example 2: Tin (Symbol Sn, neutrons=69, electrons=50)

- Electrons = Protons = 50 → Atomic Number = 50
- Symbol Sn → Confirmed on periodic table.
- Atomic Mass ≈ 50 + 69 = 119

---

Example 3: Iodine (Symbol I, Atomic Number=53, Atomic Mass=127)

- Protons = Atomic Number = 53
- Neutrons = 127 - 53 = 74
- Electrons = Protons = 53

---

Example 4: Oxygen (Symbol O, Atomic Number=8, Neutrons=8)

- Protons = 8
- Electrons = 8
- Atomic Mass = 8 + 8 = 16

---

Example 5: Chromium (Neutrons=28, Electrons=24)

- Electrons = Protons = 24 → Atomic Number = 24
- Symbol = Cr
- Atomic Mass = 24 + 28 = 52

---

Example 6: Nickel (Protons=28)

- Atomic Number = 28
- Symbol = Ni
- Neutrons = ? → We know from periodic table atomic mass ≈ 58 → 58 - 28 = 30
- Electrons = 28

---

## 🧪 TIP: Use the Periodic Table!

You can verify all symbols, atomic numbers, and atomic masses using a standard periodic table. For example:

- Gold → Au, atomic number 79, atomic mass ~197
- Platinum → Pt, atomic number 78, atomic mass ~195
- Lead → Pb, atomic number 82, atomic mass ~207

---

✔ All blanks are now filled correctly using atomic structure rules and the periodic table.

Let me know if you want this as a downloadable table or printable version!