Chemistry - Chapters 4/5 test

Democritus

Democritus

Ancient Greece. World is composed of “atmos” and empty space.

Aristotle

Ancient Greece. The world is composed of hyle (continuous matter. Ex. cats are made of cat stuff.

Lavosier

France, late 1700’s. Closed system chemical experiments led to Law of Conservation of Mass.

Proust

Germany, late 1700’s. Closed system chemical experiments lead to the law of constant composition.

Dalton

England, late 1800’s. Developed the Modern Atomic Theory. 1) Matter composed of indivisible atms (not true). 2) Atoms of the same type are identical (not true). Atoms of different types are different from each other (true). 3) Atoms combine in whole numbers to create compounds (true).

JJ Thomson

England, late 1800’s. Uses CRT experiment to prove the existence of electrons.

Milikan

USA, early 1900’s. Uses “Oil drop” experiment to calculate the coulombic charge of an electron.

Lord Rutherford

England, 1920’s. “Gold Foil” experiment proves the existence of a positively charged nucleus.

Geiger and Marsden

England, 1920’s. Used “Gold Foil” experiment to prove that atom is mostly empty space.

Walter Bothe

Germany, 1930’s. Uses x-ray diffraction to prove the existence of neutrons.

Becquerel

France, late 1800’s. Uses the “photographic plate” experiment to prove the existence of radiation.

Einstein

Germany, 1920’s. Theory of Relativity- Particles moving close to the speed of light do weird things. E = mc², mass is converted to energy during the formation of the nucleus.

Law of Definite Proportions.

Dalton. 18 g of water contains 20 g of hydrogen atoms. 180 g of water contains 200 g of hydrogen atoms.

Law of Multiple Proportions

Dalton. elements combine in whole-number ratios to form different compounds.

Protium

99%, 1 p, 0 n, 1 AMU,

Deuterium

0.8%, 1 p, 1n, 2 AMU

Tritium

0.2%, 1 p, 2 n, 3 AMU

Alpha Particle

Helium nucleus. Massive. Very little energy. Not very penetrating. Can be blocked by a sheet of paper. Dangerous if found in food.

Beta particles

A neutron. Spontaneously becomes a proton and an electron. The electron is emitted from the nucleus at high speeds (kinda dangerous). Will penetrate wood. Not very massive, but high in energy. More penetrative than alpha.

Gamma rays

High energy rays emitted from the nucleus. No mass, but more penetrative than a beta particle. Penetrates several inches of metal.

Neutron Emission

A high-speed neutron is emitted from a neutron-rich nucleus. Very penetrating due to its large mass and energy.

Thomson

“Plum Pudding”

Rutherford

Nucleus in a sea of electrons

Bohr

A planetary model

Plancks Hypothesis

• Light is given off in bundles of energy called quanta

• E = hv

• Energy = planck’s constant x wave frequency

Orbital

0 = s

1 = p

2 = d

3 = f

Bohr (atomic structure)

Emission spectra turned out to be multiple lines past the s orbital

DeBroglie

Wavelength can be predicted based on the mass and velocity of a particle (particles act like waves)

• mc² = E

• λ = h/mv

Refraction

Refraction is the bending of light as it passes from one medium to another with a different density.

Defraction

Diffraction is the bending and spreading of light waves around obstacles or through slits.

Reflection

Reflection is the bouncing back of light from a surface without changing its medium.

Heisenburg Uncertainty Principle

Both the momentum and position of a particle cannot be precisely known at the same time.

Schrodinger

Wave equations can be used to predict the region of probability for locating an electron.

Hund's Rule

electrons fill unoccupied degenerate e orbitals before pairing

Hadrons

Particles that can be subdivided into two broad classes, baryons and mesons. Neutrons and protons are hadrons.

Leptons

Light particles that are truly elementary and do not consist of smaller particles.

Baryons

A type of hadron made of three quarks, examples include protons and neutrons.

Mesons

A type of hadron made of one quark and one antiquark, examples include pions and kaons.

Quarks

Subatomic particles that make up hadrons; they come in six types: up, down, charm, strange, top, and bottom.

Gluons

Particles believed to hold quarks together by exchanging the strong force.

Antiparticles

Every particle has a corresponding antiparticle with the same mass but opposite charge; for example, the positron is the antiparticle of the electron.