Unit 1: Atoms, Elements, and Compounds 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 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 Complete activity 1-1A pg. 9

Safety Rules for the Science Lab pages 10-11 General Glassware Chemicals Hot plates and open flames Electrical equipment

W workplace H hazardous M materials I information S system 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 Toxicity The degree to which substances combine to form new compounds Combustibility The degree to which substances combine with oxygen (burn) Toxicity The degree to which a chemical is poisonous to living things

Core Lab Activity 1-2C pg. 20 Physical and Chemical Properties

Theory vs. Law A theory is less well supported than a law. Theories try to explain observations Examples: Theory of Evolution Theory of plate tectonics

Most laws are supported by different and robust experimental evidence. Laws only tell what happens, not why it happens Examples: Law of Gravity Newtons Laws of Motion

Atomic Theory The descriptions of matter and how it behaves. Has undergone many modifications as new facts became available.

Early ideas... 2000 years ago Empedocles: matter was composed of four “elements”; earth, air, water, and fire.

Democritus: eventually a substance will be cut into a piece that can no longer be cut. He called this piece atomos.

Development of Atomic Theory John Dalton (1766-1844) Billiard Ball Model 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.

Dalton’s Model... Billiard Ball Model

J.J. Thomson (1856-1940) Raisin Bun Model 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.

Thomson’s Model... Raisin Bun Model

Ernst Rutherford (1871-1937) Planetary Model He discovered that atoms have a nucleus. There are two kinds of particles in the nucleus; protons (positive charge) and neutrons (neutral).

Rutherford’s Model... Planetary Model

Niels Bohr (1885-1962) Orbital Model He proposed that electrons surround the nucleus in specific energy levels or shells. Each electron has a particular amount of energy.

Bohr’s Model... Orbital Model

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.

Summary...

Inside the Atom Subatomic Particle Charge Mass Location Proton (p+) + Large Nucleus Neutron (n) Electron (e-) - very small Energy levels

The Atom