People Flashcards
Aristotle
Matter is continuous (not made up of anything smaller)
Boyle
Believed in the atomic nature of elements, no proof, 1st scientist w quantitative values for gases
Daltons atomic theory
All matter atoms (no protons, neutrons, e)
All atoms of same element are same weight (no isotopes discovered)
Atoms cannot be divided/created/destroyed
Atoms combine in whole-number ratios to chemical compounds
In chemical rxn, atoms are combined/separated/rearranged
Thomson
ELECTRONS= electron beam in cathode ray tube deflected by electrical/magnetic field, electron CHARGE:MASS ratio
Lavoisier
Conservation of matter/mass
Proust
Law of definite proportions, substance will always have same ratio of elements by mass (H2O is 2g:16g 1g:8g)
Becquerel
Radioactivity
Uranium exposed photographic film
Curies
Radioactivity
Rays produced by Uranium+Radium spontaneously by unstable nuclei
Bohr
Electrons into shells/energy levels
Closer=less energy
2n^2=max # electrons per energy level if n=principal energy level
(n^2=max # orbitals per energy level)
De Broglie
Quantum
Particles have wavelike characteristics (diffraction patterns)
Milikan
Determine ELECTRONS charge and mass 9.11x10^-28 (1/1837th of lightest element H)
Oil drop test
Rutherford
Empty space between nucleus and electrons (SMALL dense POSITIVE NUCLEUS), atomic structure
Gold foil experiment
Some alpha particles deflected through Au
Moseley
Atomic numbers (# protons) via X-rays
Planck
Quantum
Light has particle and wavelike characteristics
Energy not continuous, released in quanta aka photon (emission spectrum releases photon light)
E=hV
Heisenberg and Schrodinger
Uncertainty principle
Impossible to know location AND velocity of subatomic particle at the same time
Wave-mechanical model: 3D e orbital cloud (unlike Bohr) treat e like waves, assign them quantum #s (sublevels, energy levels)
Paulis exclusion principle
No two electrons can have the same set of 4 quantum numbers in an atom bc the 2 e in each orbital have opposite spin
Hunds rule
Addition of electrons 1 orbital at a time
Aufbau Principle=e occupies lowest energy orbital
Mendelev
1st periodic table
Atomic weight
Democritus and Leucippus
The world is made up of empty space and tiny particles ATOMS
Chadwick
Neutron, isotopes
Einstein
Explained origin of energy released in nuclear charge
Avogadro
Equal volumes of different gases contain equal numbers of molecules at the same temperature and pressure
(1 mole=22.4 L)
Gay-Lussac
Gases in a rxn, volume of reactants and products are in small whole number ratios (1 vol H2+1 vol Cl2 = 2 vols HCl)
Le Chatelier
When a system @ equilibrium is disturbed by a stress (temp, pressure, concentration change), it will try to minimize stress to attain equilibrium
