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Chemistry Chapter 5
Quantum Numbers, Notations and Rules
| Question | Answer |
|---|---|
| de Broglie | suggested that particles of matter have the properties of waves and vice versa |
| E=hν + E=mc^2 | hν=mc^2 |
| c=λν or ν=c/λ or λ =c/ν | hc/λ =mc^2 |
| de Broglie | mathematically proved that a stream of electrons acts the same as waves of light |
| wave-particle duality of nature | refers to the two-sided nature of particles and waves |
| We know that light travels at | 3×10^8 m/sec in a vacuum |
| index of refraction | specific to a substance, is calculated by the bending of a light ray passing from a vacuum into a new substance |
| Momentum (p) | mass ×velocity and tells us where an object is going |
| Heisenberg | studied the position of an object (where it is) and the momentum of an object (where it is going) |
| Heisenberg’s Uncertainty Principle | you can’t ever know the exact position or momentum of a moving object (electron) in any given instant |
| Erwin Schrödinger | developed the theory Quantum Mechanics, which studies the behavior of very small objects at velocities near or at the speed of light |
| Newtonian Mechanics | studies the behavior of visible objects at ordinary velocities |
| 1. Primary Quantum Number | symbol: n |
| 1. Primary Quantum Number | • This number is the main energy level occupied by the electron and indicates the size of the electron cloud |
| 1. Primary Quantum Number | • Values of n range from 1-7, with n=1 being that energy level closest to nucleus |
| 1. Primary Quantum Number | • As n increases, the energy of the electron increases, as does the distance from the nucleus |
| 2. Second Quantum Number | symbol: ℓ |
| 2. Second Quantum Number | • This number indicates the sublevel and the shape of the orbital |
| 2. Second Quantum Number | • The number of sublevels in an energy level=n; sublevels are indicated by the specific levels= s, p, d, f |
| 2. Second Quantum Number | • Except in n= 1, sublevels of different shapes exist in the same energy level |
| 3. Third Quantum Number | symbol: m |
| 3. Third Quantum Number | • The number indicates the orbital and the spatial orientation of the orbital in a sublevel |
| 3. Third Quantum Number | • An orbital is an area in a sublevel that can hold 2 electrons |
| 3. Third Quantum Number | • The sublevel s has 1 orbital, p has 3, d has 5, and f has 7 |
| 4. Fourth Quantum Number | symbol: s |
| 4. Fourth Quantum Number | • This indicates the spin states of electrons in an orbital |
| 4. Fourth Quantum Number | • Values for spin is either +1/2 or -1/2 |
| 4. Fourth Quantum Number | • A single orbital holds a maximum of 2 electrons- each has an opposite spin- this explains how two negative charges can be in proximity of one another |
| Aufbau Principle | electrons occupy the lowest energy level that can receive it |
| Pauli Exclusion Principle | no 2 electrons in the same atom can have the same 4 quantum numbers |
| Hund’s Rule | orbital of equal energy are each occupied by 1 electron before any orbital is occupied by a second electron- also, all electrons in singly-occupied orbital must have the same spin |
| Diagonal Rule | after 18 electrons have been assigned to their orbital, the normal filling under Rule #1 does not apply |
| 1. electron configuration notation | Au- 1s22s22p63s23p64s23d104p65s24d105p66s24f145d9 |
| orbital notation | 1s ↑↓ |
| electron dot diagram | • for every electron in the highest energy level, place a dot around the symbol, with the s electrons on the right, and all else on top, bottom, and left |
| noble gas notation | carbon [He]2s22p2 |
| noble gas notation | • write the symbol for the noble gas which precedes the element in brackets and then add the additional electrons in the electron configuration notation |