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Grade 9 Science. Unit 1: Atoms, Elements, and Compounds. Grade 9 Science... Unit 1. Chapter 1: Atomic theory explains the composition and behaviour of matter. Lab Safety... A Review. Safety rules and procedures MUST be your top priority.
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Grade 9 Science Unit 1: Atoms, Elements, and Compounds
Grade 9 Science... Unit 1 Chapter 1: Atomic theory explains the composition and behaviour of matter.
Lab Safety... A Review • Safety rules and procedures MUST be your top priority. • Know them before you do the lab and use them while doing the lab.
Complete activity 1-1A pg. 9 Laboratory Safety
Safety Rules for the Science Labpages 10-11 • General • Glassware • Chemicals • Hot plates and open flames • Electrical equipment
WHMIS... Page 12 W workplace H hazardous M materials I information S system
Hazard Symbols... Page 13 Dangerous Container Dangerous Contents
Properties of Matter • Matter is anything that has mass and volume. • Mass is the amount of matter in a substance or object. • Volume is the amount of space a substance or object occupies.
Matter is made up of elements. • Elements are substances that contain one type of matter and cannot be broken down or separated into simpler substances.
Describing Matter 1. Physical Properties pg. 18 Characteristics of matter that are often observed or measured. Can be either qualitative (observed) or quantitative (measured).
Color • Malleability • Lustre • Conductivity • Boiling point • Melting point • Texture • Magnetism • Density
2. Chemical Properties pg. 19 Observed when substances react with each other. Determines a substances usefulness.
Reactivity • Combustibility
Core Lab Activity 1-2C pg. 20 Physical and Chemical Properties
Theory vs. Law • A law is better supported than a theory. • Most laws are supported by different and robust experimental evidence. • Theories can change or be modified • Laws rarely change
Atomic Theory • The descriptions of matter and how it behaves. • Has undergone many modifications as new facts became available.
An atom consists of a • nucleus • (of protonsand neutrons) • electrons in space about the nucleus
Early ideas... 2000 years ago • Empedocles: matter was composed of four “elements”; earth, air, wind, and fire.
460 BC • Democritus: eventually a substance will be cut into a piece that can no longer be cut. • He called this piece atomos.
Aristotle • All matter was composed of four elements • Earth, air, water and fire
Development of Atomic Theory • John Dalton - 1808 • He suggested that the particles that make up matter are like small, hard spheres that are different for different elements. • He defined an atom as the smallest particle of an element.
J.J. Thomson - 1898 • He suggested that all atoms must contain electrons (negative charge). • His model pictured a positively charged ball with the negatively charged electrons embedded in it.
Ernst Rutherford - 1910 • He discovered that atoms have a nucleus. • There are two kinds of particles in the nucleus; protons (positive charge) and neutrons (neutral).
Rutherford was able to develop Thomson’s model due to the development of new technologies. (gold foil experiment) • The development of cyclotrons and proton accelerators have further developed the model accepted today.
Rutherford’s Experiment • they fired Helium nuclei at a piece of gold foil which was only a few atoms thick. Gold foil They found that while most of the helium nuclei passed through the foil, a small number were deflected and, to their surprise, some helium nuclei bounced straight back. Helium nuclei
Rutherford’s new evidence allowed him to propose a more detailed model with a central nucleus. • He suggested that the positive charge was all in a central nucleus. With this holding the electrons in place by electrical attraction • However, this was not the end of the story.
Niels Bohr - 1913 • He proposed that electrons surround the nucleus in specific energy levels or shells. • Each electron has a particular amount of energy.
