Term
| Law of Conservation of Matter |
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Definition
Antoine Lavoisier - 1774
In chemical reactions matter is neither created nor destroyed. |
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Term
| Law of Constant Composition |
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Definition
Joseph Proust - 1799
Pure chemical compound always has the same percentage composition of each element by mass. |
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Definition
John Dalton - 1803 to 1808
1. All matter is composed of tiny, indivisible particles, called atoms, that cannot be created or destroyed.
2. Each element has atoms that are identical to each other in all of their properties, and these properties are different from the properties of all other atoms.
3. Chemical reactions are simple rearrangements of atoms from one combination to another in small whole-number ratios. |
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| Law of Multiple Proportions |
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Definition
John Dalton
When two elements can be combined to make two different compounds, and if samples of these two compounds are taken so that the masses of one of the elements in the two compounds are the same in both samples, then the ratio of the masses of the other element in these compounds will be a ratio of small whole numbers. |
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Definition
| 1834 - showed that electric current could cause chemical reactions to occur, demonstrating the electric nature of the elements. |
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Definition
Cathode rays are a fundamental part of matter he termed electrons.
He also found the charge to mass ratio of electrons. |
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Definition
| Gold foil experiment- alpha particles shot at a thin gold foil went straight through - this proved that atoms are mostly empty space. |
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Definition
| 1885 - empirical mathematical relationship between the wavelengths of light in the visible region of the spectrum. |
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Definition
| Extended Balmer's equation so that all of the wavelengths could be predicted |
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Definition
Solid particle model - 400 BC
Plum pudding model - 1909
Nuclear model - 1910 (Rutherford)
Solar system model - 1913 (Bohr)
Wave-mechanical model - 1927 (Schrödinger) |
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Definition
| 1913 - solar system model of the atom. |
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Definition
| 1900 - described light as packets, or quanta, of energy |
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Term
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Definition
| 1924 - if light can be considered as particles, then the small particles like electrons may have characteristics of a wave. |
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Definition
| 1927 - wave-mechanical theory of the atom; the electron doesn't follow a precise orbit. |
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Term
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Definition
| Heisenberg Uncertainty Principle - it is impossible to know the exact momentum and position of a particle. |
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Term
| ground state vs excited state |
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Definition
ground state - an atom that exists in the lowest possible energy state
excited state - an atom that has more energy than the ground state |
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Definition
| the distance between two repeating points on a sine wave |
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Definition
| the number of waves that pass a point in space each second |
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Definition
| (wavelength)(frequency) = speed of light |
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Term
| speed of light (in a vacuum) |
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Definition
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Term
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Definition
| the energy of electromagnetic waves is proportional to the frequency and inversely proportional to the wavelength. The proportionality constant, h, is Planck's constant. |
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Term
| How to find energy emitted when an electron drops back to the original orbit |
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Definition
| The energy emitted from an electron moving to a lower orbit can be determined by subtracting the energy of the lower orbit from the energy of the higher orbit - this results in line spectra. |
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Term
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Definition
when n (energy level) = 1, it's 53 pm.
when n = 2, it's 106 pm. |
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Term
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Definition
| there is a relationship between the particle (mass) and wave (frequency) nature of an electron. |
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Term
| The Wave-Mechanical Model |
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Definition
1. Quantum numbers are crucial
2. This changes the view of the nucleus--cloud instead of orbit.
3. This agrees with the periodic table
4. Bohr was right about the energy change and the Bohr radius |
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Term
| Heisenberg Uncertainty Principle |
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Definition
| Both the position and the momentum of an electron cannot be exactly known at the same time. The more precisely that the position of the electron is known, the more uncertainty exists as to its momentum. |
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Term
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Definition
1s, 2s, 2p, 3s, etc.
the order is s, p, d, f
can be obtained with the periodic table |
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Term
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Definition
outermost electrons
count columns on the periodic table to find them |
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Term
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Definition
| p, d, or f orbitals must all be filled with one electron before a second is allowed in |
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Term
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Definition
| arrows, representing electrons, are placed in each orbital. the second electron in each orbital has an arrow facing in the opposite direction. |
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Term
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Definition
either +1/2 or -1/2
this represents the spin of an electron |
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Term
| Pauli exclusion principle |
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Definition
| no two electrons in the same atom can have the same quantum numbers |
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Term
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Definition
n
any integer greater than one
represents the size of the principal energy level |
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Term
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Definition
l
it can be any positive integer less than n-1
represents the shape of an orbtial |
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Term
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Definition
m sub l
it can be any integer from -l to +l
it represents the orientation of each orbital in space |
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Term
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Definition
| Energy = Plank's constant * frequency |
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