The Atom Flashcards
(from MT word doc)
Democritus
proposed the idea of the atom
Aristotle
rejected the concept- he said that matter was continuous and there were only four elements (earth, air fire, & water)
John Dalton
Dalton’s Atomic Theory
- All matter is made up of atoms
- Atoms are indestructible and cannot be divided into smaller particles (atoms are indivisible)
- All atoms of one element are exactly alike, but they are different from atoms of other elements.
-the theory explains “the law of conservational mass”
Joseph Proust
developed a theory that atoms have fixed masses, “law of definite proportions”
% by mass = (mass of element/mass of compound) x 100
J.J. Thomson
cathode ray tube (think neon signs), discovered the electron, plum pudding model
Robert Millikan
early 1900s did the “oil drop” experiment determined charge and mass of electron
Ernest Rutherford (Super important)
gold foil experiment, discovered nucleus, names the proton, nuclear model
3 types of radiation?
Alpha
Beta
gamma
Alpha particles (α)
helium nucleus +2 charge, 4amu mass
when an element emits an alpha particle, it loses 4 particles and drops down 2 elements (Radium-Raidan)
Ex: Radon-222
Beta particles (β)
high speed electron emitted from the nucleus (the neutron splits, the electron is lighter so it speeds away and leaves more protons, changes mass) -1 charge, 1/1840thamu mass
Ex: I-131
Gamma rays (γ )
pure electromagnetic energy 0 charge, 0 mass
Ex: Cobalt-60
Fission
The splitting of a heavy, energetically unstable nucleus into lighter, more stable ones with the consequent release of energy.
Fusion
The coming together of two or more nuclei to produce a larger nucleus
China syndrome
when a nuclear reactor goes so critical the uranium starts boring a hole (to China…)
NIMBY
not in my backyard
