Grade 9 Science

Unit 1: Atoms, Elements, and CompoundsGrade 9 ScienceChapter 1: Atomic theory explains the composition and behaviour of matter.Grade 9 Science... Unit 1Lab Safety... A ReviewSafety 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 SafetySafety Rules for the Science Labpages 10-11GeneralGlasswareChemicalsHot plates and open flamesElectrical equipment

WHMIS... Page 12WworkplaceHhazardousMmaterialsIinformationSsystem

Hazard Symbols... Page 13Dangerous ContainerDangerous ContentsProperties of MatterMatter 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 Matter1. Physical Properties pg. 18 Characteristics of matter that are often observed or measured.Can be either qualitative (observed) or quantitative (measured).

ColorMalleabilityLustreConductivityBoilingpointMelting pointTextureMagnetismDensity

2. Chemical Properties pg. 19Observed when substances react with each other.

Determines a substances usefulness.

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

Theory vs. LawA law is better supported than a theory.Most laws are supported by different and robust experimental evidence.Theories can change or be modifiedLaws rarely changeAtomic Theory

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

An atom consists of a nucleus (of protons and neutrons) electrons in space about the nucleus

The Atom

Inside the AtomSubatomic ParticleChargeMassLocationProton (p+)+LargeNucleusNeutron (n)neutralLargeNucleusElectron(e-)-Very smallEnergy levelsEarly ideas... 2000 years agoEmpedocles: matter was composed of four elements; earth, air, wind, and fire.

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

AristotleAll matter was composed of four elementsEarth, air, water and fire

Development of Atomic TheoryJohn Dalton - 1808He 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.

Daltons Model... Billiard Ball Model

J.J. Thomson - 1898He suggested that all atoms must contain electrons (negative charge).His model pictured a positively charged ball with the negatively charged electrons embedded in it.

Thomsons Model... Raisin Bun Model

Ernst Rutherford - 1910He discovered that atoms have a nucleus.There are two kinds of particles in the nucleus; protons (positive charge) and neutrons (neutral).

Rutherfords Model... Planetary Model

Rutherford was able to develop Thomsons 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.Rutherfords Experimentthey fired Helium nuclei at a piece of gold foil which was only a few atoms thick.

Gold foilHelium nucleiThey 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.Rutherfords 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 - 1913He proposed that electrons surround the nucleus in specific energy levels or shells.Each electron has a particular amount of energy.

Bohrs Model... Orbital Model

Summary...