Unit 1: Atoms, Elements, and Compounds

Grade 9 Science

Chapter 1: Atomic theory

explains the composition and

behaviour of matter.

Grade 9 Science... Unit 1

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

Safety Rules for the Science Lab

pages 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

•Boilingpoint

•Melting point

•Texture

•Magnetism

•Density

2. Chemical Properties pg. 19

Observed

when

substances

react with

each other.

Determines a

substances

usefulness.

•Reactivity

•Combustibility

•Toxicity

Core Lab Activity 1-2C pg. 20

Physical and Chemical Properties

Theory vs. Law

A theory is less well supported

than a law.

Most laws are supported by

different and robust

experimental evidence.

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, wind, 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)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)

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)

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)

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) 0 Large Nucleus

Electron (e-) - very

small

Energy levels

The Atom