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27 Cards in this Set
- Front
- Back
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1L equals how many cm^3?
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1000 cm^3
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Density is measured in what?
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g / cm^3 or mass / volume
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Formula for volume?
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mass / density
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Molecular formula
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gives identities and numbers of atoms in a molecule
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Avagadro’s number
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6.02 x 10^23, 1mole = 6.02 x 10^23 atoms
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# of moles ?
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mass in grams / mw
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empirical formula?
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smallest whole #’s that give the same ratio of atoms in a molecule (to reduce molec. Formula divide all subscripts by greatest common factor)
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Percentage composition by mass?
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take the empirical formula molecular weight and compare individual molecule to mw.
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How do you find the empirical formula from % composition?
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-start with 100g of substance
-find the # of moles (g of substance over molec. Weight) -find the ratio of the number of atoms |
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How do you find the limiting reagent?
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convert grams to moles and look at stochiometric coefficients
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What is the oxidation state of an atom?
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the charge it would have if the compound were ionic
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What are the rules for assigning oxidation states?
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*The highest rule takes precedence
1 group 1 metals have oxidation states of +1 and group 2 of +2 2)Flourine has a -1 oxidation state 3)Hydrogen has a +1 oxidation state 4)Oxygen has a -2 oxidation state 5)Halogens have a -1 oxidation state 6)Group 16 atoms (oxygen family) have -2 oxidation state |
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What is the atomic # ?
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Z; the number of protons,
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What is a nucleon?
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central nucleus which contains protons and neutrons known collectively as nucleons
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What is the atomic mass or mass #?
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Atomic mass = protons + neutrons
A = Z + N |
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What is an isotope?
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same atomic # but differ in mass number do to the difference in neutrons
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What is an ion?
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a neutral atom that gains or looses electrons and becomes charged.
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What is the shell number, n ?
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-size and energy of the orbital
-the greater the n value the greater the electron's energy and avg. distance from the nucleus -can be any whole # starting with 1 |
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What is the subshell number,l ?
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the shape of the orbital:
l = 0 -> s subshell (groups 1,2) l= 1 -> p subshell (B - He) l= 2 -> d subshell (Sc - Zn) l=3 -> f subshell (bottom 2 periods) - l can be 0,1,2 .. n-1 |
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What is the orbital # m sub l ?
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describes 3-D orientation of orbital
-ex. if l = 2 m sub l can be -2, -1, 0, 1, 2 |
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What is the spin #, m sub s ?
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-spin of electon in orbital
-can either be +1/2 or -1/2(spin down) |
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Electron configuration rule #1?
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electrons occupy the lowest orbitals available
-electron subshells are filled in order of increasing energy |
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Electron configuration rule 2?
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Hunds rule: electrons in same subshell occupy available orbitals singly before pairing up
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Electron configuration rule #3?
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no 2 electrons in same atom can have the same set of 4 quantum #'s
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How do you write an element in the d block?
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when in the d block subtract 1 from the period number
ex. Sc; is in period 4 so you subtract 1 from the period # and say that it puts its valence electrons in the 3d subshell : [Ar] 4s2 3d1 |
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Exceptions to the rule
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Cr-> [Ar]4s1 3d5--bc atom obtains more stable, lower energy state by promoting 1 of its e's to 3d to give half filled subshell
-same concept for Mo -Cu, Ag, and Au donate electron from s subshell to give complete d subshell |
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What electrons are removed (ionized) in transition metals?
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the valence s electrons are always lost first; only after these are all gone do any d electrons get ionized
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