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33 Cards in this Set
- Front
- Back
What is a valence electron?
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an electron that resides in the outer most shell of an atom.
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The number of valence electrons is equal to the _____________ on the periodic table.
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group number
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how many valence electrons do the halogens have?
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7 valence electrons
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How many valence electrons do the noble gases have?
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8 valence electrons (except He which has 2 valence electrons)
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What are electrons repulsed by?
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Other electrons
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What are electrons attracted by?
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Protons in the nucleus
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What is an effective nuclear charge?
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the net (+) charge that an electron sees from the nucleus.
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Why can the experimental value of effective nuclear charge be greater than the calculated value?
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The probability plots of the outer electrons has regions close to the nucleus, meaning the electron sees a larger positive charge.
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Which directions does the effective nuclear charge increase on the periodic table?
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From left to right and top to bottom
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Why does the effective nuclear charge increase from left to right on the periodic table?
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Because the number of core electrons (shielding) stays the same but the number of protons increases.
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Why does the effective nuclear charge increase form top to bottom?
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Because the (# of protons)-(# of shielding electrons) remains the same down a group, but larger electron cores don't shield as well.
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What is the atomic radius?
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the distance from the center of a nucleus to outer most electrons.
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In which directions on the periodic table does the atomic radius increase?
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From right to left on the periodic table and from top to bottom.
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Why does the atomic radius increase form right to left?
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Because i decrease between the effective nuclear charge means less of an attraction of the outer electrons to the protons in the nucleus.
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Why does the atomic radius increase from top to bottom?
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Filling the electrons in the shells farther form the nucleus increases the distance.
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Do cations or anions have a smaller atomic radius than their parent atoms?
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Cations
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Do cations or anions have a larger atomic radius than their parent ions?
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Anions
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Why are cations smaller than their parent atoms?
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Because removing an outer electron means that we have a shorter distance from the nucleus to the outer electron.
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Why are anions larger than their parent atoms?
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Because by adding outer electrons means there is more distance form nucleus to outer electrons.
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what are some characteristics of metals?
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They tend to form (+) ions easily, they are easy to oxidize, react with oxygen to form basic oxides, they react with water to form hydroxides, hydrogen gas, and heat.
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In what directions does the metallic character increase on the periodic table?
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The metallic character increases form right to left and from top to bottom. This is because the hold on valence electrons get weaker.
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What is Ionization Energy?
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the energy required to remove an electron from a gaseous ground state atom or ion.
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In which directions does the ionization energy increase on the periodic table?
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From left to right and from bottom to top.
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Why does the ionization energy increase from left to right?
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because the effective nuclear charge increases, so the outer electrons are bound more tightly.
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Why does the ionization energy increase form bottom to top?
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The atomic radius is decreasing, so electrons are closer to the nucleus and bound more tightly.
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Is the first or second ionization energy larger?
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The second
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What is electron affinity?
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The affinity or willingness of a gaseous ground state ion or atom to add an electron.
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Is adding an electron usually endo or exothermic?
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Exothermic, so electron affinities are usually negative.
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In which directions do the electron affinity increase on the periodic table?
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From left to right
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Why does the electron affinity increase from left to right?
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The further right is more likely to fill a subshell.
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Why is there generally no change in electron affinity form top to bottom?
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the increase in electrons and electron repulsion is balanced out by the larger and more spread out shells.
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Do noble gases have a positive or negative electron affinity?
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A positive because it is hard to add an electron to a completely filled sub shell.
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Why do the group 5 elements have more positive electron affinities?
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Because they already have a half full sub shell, it is difficult to add an electron to a half filled sub shell.
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