Chemistry Basics 10

Matter and Its Nature

1. Definition of Matter: Anything that has mass and occupies space.
2. States of Matter:
○ Solid: Definite shape and volume.
○ Liquid: Definite volume, no definite shape.
○ Gas: Neither definite shape nor volume.
3. Physical and Chemical Properties:
○ Physical: Can be observed without changing the substance (e.g., color, melting
point).
○ Chemical: Observed during a chemical reaction (e.g., reactivity, flammability).




Atomic Structure

1. Atom: Smallest unit of matter, composed of protons, neutrons, and electrons.
2. Subatomic Particles:
○ Proton: Positive charge (+1), mass ≈ 1 amu.
○ Neutron: Neutral charge, mass ≈ 1 amu.
○ Electron: Negative charge (-1), negligible mass.
3. Atomic Number (Z): Number of protons in the nucleus.
4. Mass Number (A): Sum of protons and neutrons.
5. Isotopes: Atoms of the same element with different numbers of neutrons (e.g.,
Carbon-12 and Carbon-14).




Periodic Table

1. Groups: Vertical columns; elements in the same group have similar chemical properties.
2. Periods: Horizontal rows; properties change progressively across a period.
3. Classification:
○ Metals: Good conductors of heat and electricity (e.g., iron, aluminum).
○ Nonmetals: Poor conductors (e.g., oxygen, sulfur).
○ Metalloids: Properties of both metals and nonmetals (e.g., silicon).




Chemical Bonding

1. Types of Bonds:
○ Ionic Bond: Transfer of electrons between metals and nonmetals (e.g., NaCl).
○ Covalent Bond: Sharing of electrons between nonmetals (e.g., H₂O).