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G8: Science (Version II)

Unit 3, Module 1: The Particle Nature of Matter

Properties
characteristics that describe a sample of matter

Mass
a measure of the amount of matter the object has

Volume
the measure of the space occupied by an object

Matter
occupies space, has mass and volume

Atom
the smallest particle of an element that has all the properties of the element

Leucippus & Democritus
believed that nature consisted of two things, atoms and the void that surrounds them.

Democritus
"Atoms are physically, but not geometrically, indivisible. They are indestructible and completely full, so there is no empty space." He called these particle "atomos", a Greek words which means indivisible particle.

John Dalton-
presented concrete evidence that all matter is made of very small particles called atoms

Molecule-
a particle consisting of two or more atoms combined together in a specific arrangement

Angstrom-
a unit of length equal to one ten millionth of a millimetre used to measure the size of an atom

States of Matter:

Solids
These have definite shapes and volume because the particles are packed closely together in fixed positions. They vibrate a little but they cannot move around.

Liquids
The particles are close to one another, nudging each other as they move. The attraction between particles in stronger than those in gases. They move and change positions but not as freely as those in a gas.

Gases
They take the shape of the container because the particles are able to move freely to all parts of the container. They are far apart and there is negligible attraction between them. The distances between particles are so large and so there is more room for particles to move closer to each other.

Plasma
a form of matter in which many of the electrons wander around freely among the nuclei of the atoms (not from the module)

Bose-Einstein Condensate
any system of bosons that occupy the same quantum ground state (not from the module)

Physical & Chemical Changes:

Physical Change
doesn't change what the substance is. It can be reversed.

Chemical Change
there is a chemical reaction and a new substance is formed. It cannot be reversed without extraordinary means, if at all.

Phase Changes of Matter:

Freezing
liquid -> solid

Melting
solid -> liquid

Condensation
  gas -> liquid

Vaporization
liquid -> gas

Sublimation
solid -> gas (without going through liquid)

Deposition
gas -> solid (without going through liquid)

Laws of Chemical Combination:

Law of Conservation of Mass
States that mass can neither be created nor destroyed. It was formulated by Antoine Lavoisier.

Law of Constant Proportions
States that when a compound is broken, the masses of the constituent elements remain in the same position. This was formulated and proved by Joseph Louis Proust.

Law of Multiple Proportions
States that when two elements form 2 or more compounds between them. This was proposed by John Dalton and it's not a combination of the precious laws.

Atomic Number
the number of protons in the nucleus of an atom

Atomic Mass
the number of protons and neutrons in the atom

Isotopes
atoms with the same number of protons but different number of neutrons

Ions
a charged atom/molecule

Anions
negatively charged atoms

Cations
positively charged atoms

Atomic Orbitals:

S-Orbitals
(sharp) 2 electrons

P-Orbitals
(principal) 6 electrons

D-Orbitals
(diffused) 10 electrons

F-Orbitals
(fundamental) 14 electrons