Question | Answer |
Scientists involved in the development of the atomic theory | Democritus, Dalton, Thomson, Millikan, Rutherford, Bohr |
John Dalton Postulate 1 | Matter is made up of tiny, indivisible particles called atoms which can't be created or destroyed. |
John Dalton Postulate 2 | Atoms of the same element are identical in mass and size and are different from other elements |
John Dalton Postulate 3 | Atoms combine in small whole-number ratios to form compounds. |
John Dalton Postulate 4 | In reactions, atoms are combined, separated, and rearranged. |
J.J. Thomson | Discovered ELECTRONS using the cathode ray tube. He concluded that they were negatively charged and there must be positively charged particles to balance out the charge. |
Robert Millikan | Performed the oil drop experiment and determined the charge to be negative by measuring the amount of current needed to keep oil drops suspended. |
Ernest Rutherford | Discovered atom's nucleus with alpha-particles and gold foil. Concluded that most of the atom is empty space and that the nucleus is very small. |
1st Quantum number: Principal (n) | main energy level: values range from 1 --> ? |
2nd Quantum number: azimuthal (l) | number of sub shells and orbital shape: values range from
0 --> n - 1 .... 0 = s 1 = p 2 = d 3 = f |
3rd Quantum number: magnetic (ml) | number of spacial orientations of orbital values range from
-l --> +l |
4th Quantum number: spin (ms) | axial rotation of electrons: values are +1/2 or -1/2 |
Aufbau Principle | An electron will occupy the lowest possible energy orbital that will receive it. Empty orbitals overlap in their energies at higher main energy levels and should be filled in order according to diagonal rule. |
Hund's Rule | When filling orbitals of equal energy electrons of the same spin will occupy each orbital as singles before pairing. Empty bus seat rule. |
Pauli Exclusion Principle | No two electrons of the same atom will have the same 4 quantum numbers. |