Lecture Notes on Atoms and Molecules

Introduction to Matter

Definition of Matter: Everything around us is made of matter.
Types of Matter: Includes a vast variety of objects, e.g., tires, animals, plants, and more.
Matter Composition: All matter is made up of tiny pieces, which we call atoms.

Definition of Atoms: The fundamental building blocks of matter. The term "atom" comes from the Greek word meaning "uncuttable."
Size of Atoms: Atoms are extremely small, with the ability to fit one million atoms on the head of a pin.
Structure of Atoms:
- Nucleus: Contains protons (positive charge) and neutrons (neutral charge).
- Electrons: Very small particles that orbit the nucleus and are negatively charged.
- Empty Space: Atoms are mostly empty space between the nucleus and the electrons.

Electricity: The flow of electrons from one atom to another is referred to as electricity.
Solid State: Despite being mostly empty, atoms behave like solids because of the strong repulsion between electrons.

Definition of Molecules: When atoms combine, they form molecules (like letters form words).
Example: Water (H2O) is made of two hydrogen atoms and one oxygen atom.
Experiment: Passing electricity through water separates it into hydrogen and oxygen gases, illustrating molecule composition.

Organization of Elements: Elements are grouped into periods on the periodic table based on the number of protons in their nuclei.
Atomic Number: Indicates the number of protons in the nucleus, defining each element.
Examples of Elements: Salt (NaCl), Water (H2O), Sugar (C6H12O6).

Carbon's Role: Carbon is essential for life and is found in all living things. It is the basis for organic chemistry.
Carbon Compounds: Carbon forms various molecules that are crucial for biological processes.

Everything in the universe is either matter or energy. Matter is composed of atoms, while energy can be associated with the interactions of those atoms.
Final Thoughts: Atoms and molecules are everywhere, forming the basis of all matter and life.