chemistryform 4- chapter 2

7/30/2019 chemistryForm 4- Chapter 2

1/21

CHEMISTRYFORM 4

CHAPTER 2

~THE STRUCTURE OF THE ATOM~


2/21

MATTER

MATTER

-Occupiesspace and hasmass

-Includes allliving and nonliving things

ELEMENTS

ATOMS

-Exp: Copper(Cu)

MOLECULES-Exp: Oxygen

gas(O2)

COMPOUNDS

IONS

-Exp: Salt (NaCl)

MOLECULES-Exp: water

(H2O),Carbon

dioxide gas(CO2)


3/21

KINETIC THEORY OF MATTER

Explains the state of matter in solid, liquid and gaseous statesbased on the following assumptions:

a)Matter is made up of tiny and discrete particles

b)Particles are always vibrating ormoving and colliding

with each other.

c)Particles often move randomly

d)There are attractive forces between the particles, these

attraction will increase as the distance between the particles

become closer

e) The higher the temperature, the higher the kinetic energy ofthe particles

f)This theory can be proven by the diffusion of particles (a

process whereby particles ofdifferent matters mix slowly

due to random movement of the particles


4/21


5/21

CHARACTERISTICS SOLID LIQUID GAS

ARRANGEMENT OF PARTICLES -Particles are arranged

closely, packed orderly and

in a fixed position

-There are little emptyspaces between the

particles

-Particles are not arranged

in order

-There are empty spaces

between the particles-Most particles are still in

contact with one another

-Particles are not arranged

in order but separated from

each other

MOVEMENT OF PARTICLES -Particles are not free to

move and only vibrate at a

fixed position

-Particles move randomly

and slowly ,colliding with

each other

-Particles move randomly

and rapidly in all directions.

-The particles often collide

against each other

FORCE OF ATTRACTIONBETWEEN THE PARTICELS

Very strong Moderate Very weak

ENERGY CONTENT Very low Moderate Very high

SHAPE Fixed Follows the container Fills the whole container

VOLUME Fixed Fixed Not fixed

ABILITY TO COMPRESS No Difficult Yes


6/21

CHANGES IN STATE OF MATTER


7/21

PROCESS STATE OF MATTER EXPLANATION

MELTING -When heated, heat energy isabsorbed by the particles of

the solid.

-Particles obtain more energy

and vibrate at a faster rate-At the melting point, particles

obtain enough energy to

overcome the force of

attraction between particles

-Particles can now move

freely, solid melts into liquid

BOILING -when heated ,heat energyabsorbed by the liquid will

cause the particles to move

faster

-At the boiling point, theenergy obtained will allow the

liquid to overcome the force

of attraction between the

particles

-The liquid particles move

freely to form a gas


8/21

PROCESS CHANGES IN STATE OF

MATTER

EXPLANATION

SUBLIMATION -when heated the heat

energy that is absorbed by

the liquid-The solid particles

separate from the lattice

and are released to the air

-the solid particles directly

changes to gas

FREEZING -When a liquid is cooled,

the particles loose energy

,and are pulled closer by

the strong forces between

the particles.

-This reduces the ability ofthe liquid to move freely

-The liquid solidifies to

form a solid


9/21

PROCESS CHANGE IN STATE OF

MATTER

EXPLANATION

CONDENSATION -When a gas has cooled,

the gas particles will lose

their energy and move

slower-The attractive forces

between the particles will

pull the particles closer to

each other

-the distance between gas

particles will be closer and

this changes the gas toliquid

SUBLIMATION (2) -when a gas has cooled, the

gas particles lose their

energy and move at slower

speeds-The gas particles are then

pulled together

by the strong attractive

forces between the

particles.

Thus the gas will turn into

solid


10/21

NAPHTHALENE HEATING CURVE


11/21

NAPHTALENE COOLING CURVE

SUPER COOLING


12/21

ATOMIC THEORIES

Scientist &

approximate Date

Name of Model,

Sketch

and main idea of

theory

Importance andImprovement on

previous model

Shortcomings -

Problems

or why was it

changed

Democritus

c.300 BC

Atom the indivisible

particle

Atomos (in ancient

Greek) means "that

which cannot be

further broken down

into smaller pieces".

Talks about the

atom as the smallestparticle of matter.

Defines the atom as

an indivisible particle

Explains certain

natural occurrences

such as the existenceof elements

Does not give a

scientific view of theatom only a

conceptual definition

Does not talk about

subatomic particles

(Electrons, Protons,

Neutrons)


13/21

Dalton

c.1800

The solid sphere

model

Atoms are seen as

solid, indestructiblespheres (like billiard

balls)

Explains a lot of

chemical properties

such as how atoms

combine to form

moleculesExplains chemical

change better than

the Particle Theory

Confirms the basic

Laws of Chemistry:

Conservation of

Mass & definite

Proportions

Does not include

the existence of the

nucleus

Does not explain

the existence of ionsor isotopes

Does not talk about

subatomic particles

(Electrons, Protons,

Neutrons)
http://www.clickandlearn.org/gr9_sci/Particle_Theory.htmhttp://www.clickandlearn.org/gr9_sci/Particle_Theory.htm


14/21

J.J. Thomson

c.1850

The raisin bun

Model or the

chocolate chip

cookie model :

Atoms are solidspheres made-up of

a solid positive mass

(or core) with tiny

negative particles

embedded in the

positive core.

Infers on the

existence of

electrons and

protons

Introduces theconcept of the

nucleus

Infers on the

relative nuclear

density and atom

mass of different

atoms

Does not explain

the existence of

electrons outside

the nucleus does

not explain the roleof electrons in

bonding

Does not talk about

neutrons therefore

can't explain

radioactivity and

the existence of

isotopes


15/21

Rutherford

c. 1905

The Planetary

Model

Famous Gold Leaf

Experiment proves

that the nucleus is

positive and the

electrons are

outside the nucleus.

First real modern

view of the atom

Explains why the

electron spins

around the nucleus

(Bohr'sContribution)

Proposes that the

atom is really

mostly empty space

Does not place

electrons in definite

energy levels

around the nucleus

Doesn't include

neutrons in the

nucleus

Does Not relate the

valence electrons

atomic charge
http://www.clickandlearn.org/gr9_sci/atoms/rutherford.htmlhttp://www.clickandlearn.org/gr9_sci/atoms/rutherford.htmlhttp://www.clickandlearn.org/gr9_sci/atoms/rutherford.htmlhttp://www.clickandlearn.org/gr9_sci/atoms/rutherford.htmlhttp://www.clickandlearn.org/gr9_sci/atoms/rutherford.htmlhttp://www.clickandlearn.org/gr9_sci/atoms/rutherford.htmlhttp://www.clickandlearn.org/gr9_sci/atoms/rutherford.htmlhttp://www.clickandlearn.org/gr9_sci/atoms/rutherford.htmlhttp://www.clickandlearn.org/gr9_sci/atoms/rutherford.htmlhttp://www.clickandlearn.org/gr9_sci/atoms/rutherford.html


16/21

(Neils Bohr)Bohr- Rutherford

c. 1920

Electrons in Definite

energy Levels

around the nucleus

Used atomic spectra

to prove thatelectrons are placed in

definite orbitals

(called shells) around

the nucleus.

Explains the role of

valence electrons in

bonding

Relegates the

number of valenceelectrons to the

Periods of a periodic

table

Fully explains ionic

and covalent bonding

Places electrons in

definite energy levels

2 e- in the first

8 e- in the second

8 e- in the third

It does not explain

the shapes of

molecules or other

abnormalities that

result form unevenlyshared pairs of

electrons (such as the

abnormal behaviour

of water, the

difference in Carbon-

Carbon Bondsbetween diamond and

graphite )


17/21

Modern Theory

Many Scientists

Contributed. Some

of the more

famous are:

Schroedinger

Einstein

Luis De Broglie

Max Planck

Frank Hertz

Maxwell

Fermi

Quantum

Mechanical Model

or Electron Cloud

Model The analogy

here is that of a

"beehive" where

the bees are the

electrons moving

around the nucleus

in a "cloud" ofenergy levels.

Advanced theories

explain about the

behaviour of atoms

and their chemicaland physical

properties in

forming new

compounds.
http://www.clickandlearn.org/chemistry/atomic%20theory.htmhttp://www.clickandlearn.org/chemistry/atomic%20theory.htmhttp://www.clickandlearn.org/chemistry/atomic%20theory.htmhttp://www.clickandlearn.org/chemistry/atomic%20theory.htm


18/21

SUBATOMIC PARTICLES


19/21

SYMBOLS OF ELEMENTS


20/21

EXAMPLES OF ISOTOPES:


21/21

chemistryform 4- chapter 2

Documents