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19 Cards in this Set
- Front
- Back
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How were Dalton's Atomic ideas an improvement over Democritus's ideas? |
Democritus reasoned that atoms were indivisible and indestructible. Dalton transformed Democritus's ideas on atoms into a scientific tragedy using experimental methods.
Dalton's atomic theory: 1. All elements are composed of tiny indivisible particles called atoms. 2. Atoms of the same element are identical. The atoms of any one element are different from those of any other element. 3. Atoms of different elements can physically mix together or can chemically combine in simple whole-number ratios from compounds. 4. Chemical reactions occur when atoms are separated from each other, joined, or rearranged in a different combination. Atoms of one element, however, are never changed into atoms of another element as a result of a chemical reaction.
His improvement over Democritus included #4. |
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Describe the charge and density of the nucleus of an atom. |
The nucleus has a positive charge and is the most dense part of the nucleus. |
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How is the mass number of an atom calculated? |
The mass number is the sum of the number of neutrons and protons of the atom. |
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What is the same for all atoms of a particular element? |
The atomic number and thus the number of protons is the same for all atoms of a particular element. |
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How are isotopes of the same element different? |
Because they are the same atom, the number of protons is the same but isotopes differ in their numbers of neutrons. |
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Atomic Number:
# protons - # electrons |
Mass Number:
# protons + # neutrons |
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Carbon-14
6 protons, 8 neutrons. 6 electrons |
Al-27
13 protons, 14 neutrons, 13 electrons
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How are atoms of one element different of one element different from those of another element?
How are atoms of one isotope different from other isotopes of the same element? |
They have differing numbers of protons.
Although the number of protons is the same, the number of neutrons differs. |
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An element X has two naturally occuring isotopes: X-79 (abundance=50.69%. mass=78.198 amu) and X-81 (abundance=49.31%, mass=80.917 amu). Calculate that weighted atomic mass of X. Also, identify the unknown element which exists as a reddish-brown gas and is a liquid at room temperature. |
% abundance X mass + % abundance X mass = average mass
(.5069)(78.198 amu) + (.4931)(80.917 amu) = 70.53 amu Bromine |
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Why is it impossible to measure both the position and the velocity of an electron at the same time with accuracy? |
The energy used to measure these values changes both the position and the velocity. (Heisenberg uncertainity principle). |
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What is the minimum amount of energy that can be gained or lost by an atom? |
quantum |
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What is the correct ground state of Carbon? |
1s²2s²2p² |
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What is the order of filling for orbitals found in the 5th energy level? |
s, p, d, f |
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How many sublevels are present when the principal number is 4? |
# sublevels = n (4) |
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How many orbitals are present in the 6th energy level? |
# orbitals = n² (36) |
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How many electrons are found when the principal quantum number is 3? |
# electrons = 2n² (18) |
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The part of visible light has a frequency of 7.32 X 10¹⁴ s⁻¹. Calculate the wavelength. |
c=wavelength X frequency c=speed of light (3.00 X 10⁸ m/s) v=frequency (7.32 X 10¹⁴ s⁻¹) wavelength = speed of light/frequency
3.00 X 10⁸ m/s _________________ = 4.10 X 10⁻⁷ m 7.32 X 10¹⁴ s⁻¹
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Calculate the energy of radiation with a wavelength of 634nm. |
wavelength = 634nm X 1m ________ = 6.34X10⁻⁷m 1 X 10⁹ nm c = 3.00 X 10⁸m/s h = Planck's constant = 6.626 X 10⁻³⁴ Js E = hc __________ = (6.626X10⁻³⁴Js)(3.00X10⁸m/s) wavelength _______________________________ 6.34X10⁻⁷m
=3.14 X 10⁻¹⁹ J
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Write the orbital diagram and the electron configuration for Francium. How many valence electrons does Francium have? |
electron diagram: 1s²2s²2p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6p⁶7s¹
Francium has one valence electron. |
