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Intro to Chemistry

Atomic Structure and Atomic Weight

In chemistry, an atom is the smallest constituent unit of ordinary matter that has the properties of a chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are very small; typical sizes are around 100 picometers. The word "atom" comes from the Greek (atomos), meaning "indivisible". In the past, the word "atom" was used for the smallest possible division of a substance, which was assumed to be indivisible. As modern chemistry developed, it became apparent that this assumption, while useful in many ways, was incorrect; it was found that atoms can be divided into smaller particles, such as electrons and protons, and that the nucleus of the atom consists of still smaller particles, such as neutrons and protons. The term "atom" is now used for two different concepts: a particle which is the smallest constituent unit of ordinary matter, and a set of particles which (as a whole) has a unique mass and composition, and which is almost always an electrically neutral system.

Kim Pham

Intro To Chem - Introduction

Classification and Properties of Matter

Fundamentals of Energy

Units of Measurement

Uncertainty in Measurement

Accuracy and Precision

Dimensional Analysis

Atomic Theory and the Nuclear Model

Atomic Structure and Atomic Weight

The Periodic Table

Inorganic Compounds

Organic Compounds

Example 1

Example 2

Example 3

Example 4