atomic theory worksheets

📚 Topic Summary

Atomic theory is the foundation of chemistry and physics, explaining that all matter is composed of tiny particles called atoms. These atoms combine to form molecules and compounds. Understanding the structure of the atom, including protons, neutrons, and electrons, is crucial for comprehending chemical reactions and the properties of different substances. This worksheet will help you solidify your understanding of these fundamental concepts.

⚛️ Part A: Vocabulary

Match the terms with their definitions:

1. Atom
2. Proton
3. Neutron
4. Electron
5. Isotope

Definitions:

1. A particle with a positive charge found in the nucleus.
2. An atom with the same number of protons but a different number of neutrons.
3. A stable particle with no charge found in the nucleus.
4. The smallest unit of matter that retains the chemical properties of an element.
5. A particle with a negative charge that orbits the nucleus.

Answer Key:

1-4, 2-1, 3-3, 4-5, 5-2

🧪 Part B: Fill in the Blanks

Complete the following paragraph using the words provided:

Nucleus, Electrons, Protons, Atomic Number, Mass Number

The center of an atom is called the __________. It contains __________ and neutrons. The number of __________ in an atom determines its __________ which identifies the element. The sum of protons and neutrons is the __________. __________ orbit around the nucleus in energy levels or shells.

Answer Key: Nucleus, Protons, Protons, Atomic Number, Mass Number, Electrons

🤔 Part C: Critical Thinking

Explain how the discovery of isotopes challenged Dalton's original atomic theory.