Everything you see — the air, your notebook, even you — is made of atoms.
Understanding atoms means understanding the universe itself.”
Cognitive: Explain the structure of atoms and distinguish between elements, atoms, and subatomic particles.
Affective: Appreciate the importance of atomic theory as the foundation of all physical sciences.
Psychomotor: Identify atomic parts and use the periodic table to interpret atomic information.
🧠 Key Concepts:
Matter is anything that has mass and occupies space.
All matter is made of tiny particles called atoms.
Atom: the smallest unit of matter that retains the properties of an element.
Atom: smallest particle of matter that can exist independently.
Element: a pure substance made up of only one kind of atom.
🔢 Atomic Number
Number of protons in an atom’s nucleus.
It defines the identity of an element.
💡 Example: Hydrogen (1), Oxygen (8)
⚖️ Mass Number
Total number of protons + neutrons.
🧬 Isotopes
Atoms of the same element with the same number of protons but different neutrons.
Examples:
Carbon-12, Carbon-13, Carbon-14
Hydrogen-1 (protium), Hydrogen-2 (deuterium), Hydrogen-3 (tritium)
🧠 All isotopes of an element have similar chemical properties but different masses.
“The periodic table is your map of the elements — every box tells a story about the atom it represents.”
Here’s how to read it:
🧮 Example Calculation (Oxygen):
Atomic number = 8 → protons = 8, electrons = 8
Atomic mass ≈ 16 → neutrons = 16 − 8 = 8