| A | B |
|---|
| Democritus | believed matter made of extremely small particles that could not be divided |
| Discontinuous (Atomic) Theory | matter divides only to small particles (atoms) |
| Aristotle | believed there was no limit to the number of times matter could be divided |
| Continuous Theory | matter can be divided into smaller and smaller pieces with no limit |
| John Dalton | evidence for the existence of atoms by measuring the masses of elements |
| Dalton's Atomic Theory | all matter is made up of individual particles called atoms, which cannot be divided |
| J. J. Thomson | experiments provided the first evidence that atoms are made of even smaller particles |
| Thomson Model of Atom | negative charges evenly scattered in atom filled with a positively charged matter |
| Ernst Rutherford | scientist who did Gold Foil Experiment |
| Gold Foil Experiment | most alph particles pass through foil, few deflected, even less bounce back |
| atomic nucleus | dense, positively charged mass located in the center of the atom |
| Rutherford Model of Atom | all of an atom’s positive charge is concentrated in its nucleus, most of atom is empty space |
| subatomic particles | protons, electrons, neutron |
| proton | positively charged subatomic particle that is found in the nucleus of an atom |
| electron | negatively charged subatomic particle that is found in the space outside the nucleus |
| neutron | neutral subatomic particle that is found in the nucleus of an atom |
| James Chadwick | discoverer of the neutron |
| charge on electron | -1 |
| charge on proton | +1 |
| charge on neutron | 0 (no charge) |
| relative mass of proton | 1 atomic mass unit |
| relative mass of electron | 1/1836 atomic mass unit |
| symbol for electron | e- |
| symbol for proton | p+ |
| symbol of neutron | n |
| actual mass of proton | 1.674 x 10^-24 grams |
| actual mass of neutron | 1.675 x 10^-24 grams |
| actual mass of electron | 9.11 x 10^-28 grams |
| atomic number | number of protons in an atom of an element |
| mass number | sum of the protons and neutrons in the nucleus of that atom |
| number of neutrons | Mass number minus Atomic number |
| isotopes | same atomic number but different mass numbers due to different numbers of neutrons |
| oxygen-18 | 8 p+, 8 e-, 10 n |
| oxygen-17 | 8 p+, 8 e-, 9 n |
| oxygen-16 | 8 p+, 8 e-, 8 n |
| hydrogen-1 (protium) | 1 p+, 1 e-, 0 n |
| hydrogen-2 (deuterium) | 1 p+, 1 e-, 1 n |
| hydrogen-3 (tritium) | 1 p+, 1 e-, 2 n |
| Bohr Model of Atom | electrons in energy levels out side of nucleus |
| electron rises to higher energy level | energy gained |
| electron falls to lower energy level | energy lost |
| Louis de Broglie | electrons act as particles and waves |
| Erwin Schrodinger | equations describing electron motion |
| Electron Cloud Model of Atom | describe the possible locations of electrons around the nucleus |
| electron cloud | visual model of the most likely locations for electrons in an atom |
| orbital | region of space around the nucleus where an electron is likely to be found |
| number of orbital in level 1 | 1 |
| maximum number of e- in level 1 | 2 |
| number of orbital in level 2 | 4 |
| number of orbital in level 3 | 9 |
| number of orbital in level 4 | 16 |
| maximum number of e- in level 2 | 8 |
| maximum number of e- in level 3 | 18 |
| maximum number of e- in level 4 | 32 |
| electron configuration | arrangement of electrons in the orbitals of an atom |
| stable electron configuration | electrons are in orbitals with the lowest possible energies |
| ground state | electron possessing lowest energy possible |
| excited state | electrons move to higher energy level |
| Heisenberg Uncertainty Principle | position and momentum of an electron CANNOT both be known |
| Principle Quantum Number (n) | describes energy level |
| Second Quantum Number (l) | describes energy sublevels |
| Third Quantum Number (m) | describes orbitals in sublevels |
| Fourth Quantum Number | describes electron spin |
| Sublevels of Energy Level 1 | s sublevel |
| Sublevels of Energy Level 2 | s and p sublevels |
| Sublevels of Energy Level 3 | s, p and d sublevels |
| Sublevels of Energy Level 4 | s, p, d, and f sublevels |
| Aufbau Principle | electrons fill lowest energy orbitals first |
| Pauli Exclusion Principle | electrons in same orbital have different spin |
| Hund's Rule | all orbitals in level must have one e- before e- will double up |
| valance electrons | electrons in elements last occupied energy level |
| electron dot diagram | represents valance electrons |
| configuration of H | 1s1 |
| configuration of He | 1s2 |
| configuration of Li | 1s2 2s1 |
| configuration of Be | 1s2 2s2 |
| configuration of B | 1s2 2s2 2p1 |
| configuration of C | 1s2 2s2 2p2 |
| configuration of N | 1s2 2s2 2p3 |
| configuration of O | 1s2 2s2 2p4 |
| configuration of F | 1s2 2s2 2p5 |
| configuration of Ne | 1s2 2s2 2p6 |
| configuration of Na | 1s2 2s2 2p6 3s1 |
| configuration of Mg | 1s2 2s2 2p6 3s2 |
| configuration of Al | 1s2 2s2 2p6 3s2 3p1 |
| configuration of Si | 1s2 2s2 2p6 3s2 3p2 |
| configuration of P | 1s2 2s2 2p6 3s2 3p3 |
| configuration of S | 1s2 2s2 2p6 3s2 3p4 |
| configuration of Cl | 1s2 2s2 2p6 3s2 3p5 |
| configuration of Ar | 1s2 2s2 2p6 3s2 3p6 |
| configuration of K | 1s2 2s2 2p6 3s2 3p6 4s1 |
| configuration of Ca | 1s2 2s2 2p6 3s2 3p6 4s2 |
| configuration of Sc | 1s2 2s2 2p6 3s2 3p6 4s2 3d1 |
| configuration of Ti | 1s2 2s2 2p6 3s2 3p6 4s2 3d2 |
| configuration of V | 1s2 2s2 2p6 3s2 3p6 4s2 3d3 |
| configuration of Cr | 1s2 2s2 2p6 3s2 3p6 4s1 3d5 |
| configuration of Mn | 1s2 2s2 2p6 3s2 3p6 4s2 3d5 |
| configuration of Fe | 1s2 2s2 2p6 3s2 3p6 4s2 3d6 |
| configuration of Co | 1s2 2s2 2p6 3s2 3p6 4s2 3d7 |
| configuration of Ni | 1s2 2s2 2p6 3s2 3p6 4s2 3d8 |
| configuration of Cu | 1s2 2s2 2p6 3s2 3p6 4s1 3d10 |
| configuration of Zn | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 |
| diagonal rule | helps determine lowest energy sublevels |
