Section 2 - Matter & Chemical Change

In the stone age (8000 BC)...

Stone was used to make tools (Ex. Glass and ceramics)

In 6000 BC to 1000 BC....

Valuable metals were used (gold, copper)

In the bronze age (4500 BC)....

Copper and tin were used to create bronze for weapons

In the iron age (1200 BC)...

Middle easterners learned to extract iron from rocks

Democritus:

Greek philosopher who believed that atoms (atomos: indivisible) were particles that could not be broken down further.

Aristotle:

Well known and respected but his theory of everything on earth being made of earth, fire, wind and water was untrue

Alchemy (350 BC) was...

The earliest form of experimenting with chemicals to create new things (Half-Magician, Half-Scientist)

Al Razi:

Early alchemist who discovered changes in state of matter and how it worked (Plaster of Paris)

Andreas Libeau: (German alchemist)

Made the first chemistry text ever printed (1597)

Robert Boyle (Irish aristocrat, 1660):

Observed the nature of chemicals/Discovered gas properties and behavior under pressure

Antoine Laurent Lavosier (French scientist with wife in 1770's)

Developed system for naming chemicals based on their interactions ("father of modern chemistry")

John Dalton:

Suggested matter was made of elements, came up with the structure of an atom and that elements are made of atoms (Billiard Ball)

J.J. Tomson: (British Physicist, 1897)

First to discover subatomic particles (electrons), (Raisin Bun)

Hantaro Nagaoka: (Japanese physicist, 1904)

Atom \= mini solar system

Ernest Rutherford: (British Scientist, 1911)

Supported existence of a nucleus in atoms

Niels Bohr: (Danish researcher, 1913)

Furthered the model of an atom where electrons do not randomly orbit but jump over shells and gain energy (electron orbit)

Structure of Atoms...

(P.E.N) Protons (+) Electrons (-) Neutrons (\=)

Dalton's Symbols:

Symbols used to organize elements for all chemists (John Dalton)

Atomic Mass:

Total mass of all the protons and neutrons in an atom

Atomic Number:

Shows how many protons (and electrons) are in nucleus of an element

The center of an atom is...

A nucleus

Demitri Mendeleev:

Russian chemist who created an organized system for the elements which correspond them with their patterns and properties (periodic table)

Alkali metal...

A very reactive metal

Halogen...

A very reactive non-metal

Element...

A pure substance of the same atoms

Compound...

A combination of two or more elements

Noble gas..

An unreactive non-metal

Period:

A horizontal row of elements in the periodic table

Group/Family:

A vertical column of elements in the periodic table

What are the physical properties of matter?

The appearance and composition of a substance (Ex. Color, luster and melting point)

What are the chemical properties of matter?

How a substance interacts with other substances (Ex. Reaction to water and acids as well as reaction to heat)

Physical Change:

Change in the appearance or state of a substance that doesn't change the composition of it

Chemical Change:

Change that happens when 2 substances react to create other substances which results in completely different properties

Mechanical mixture:

Mixture in which the substances that make the mixture are visible (heterogeneous mixture)

Solution:

Mixture of two or more pure substances that looks like one substance (homogenous mixture)

Model of an atom:

At the center of the atom is a tiny, dense nucleus containing protons and neutrons. Surrounding the nucleus is a cloud like region of moving electrons called the electron cloud.

Mixture:

Combination of two or more elements

Suspension:

Cloudy mixture where tiny particles of one substance are held within another and the particles can be separated out

Colloid:

Cloudy mixture in which tiny particles of one substance are held within another but particles cannot be separated out from the other substance

Property:

Characteristic used to describe a substance

James Chadwick

Discovered the neutron (\=) and proton (+)

Atoms are all about:

Stability

Metals

Shiny, malleable, ductile, conduct electricity

Metalloids

Have both metallic and non-metallic properties

Non-Metals

Solid (dull & brittle) or gases, don't conduct electricity (insulators)

Alkaline earth metals:

Very reactive metals but not as reactive as Alkali metals