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35 terms

Chemistry #3

chemistry #3
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subatomic particles
proton, neutrons & electrons
nucleons
protons + neutrons
all subatomic particles found in the nucleus
electron cloud
outer region of an atom which contains all electrons
volume
atomic number
Z = # of protons = # of electrons

this is an undisturbed atom is electrically neutral
mass number
A = # of neutrons + # of protons (Z)
# of neutrons
A - Z = # of neutrons
element
a pure substance in which all atoms present have the same atomic number
isotopes
1. are atoms of an element that have the same number of protons and electrons, but different number of neutrons
2. atoms with identical atomic numbers but different mass numbers. physical properties are slightly different
the chemical properties are the same, but the physical properties are different
atomic mass
is the calculated average mass for the isotopes of an element, expressed on a scale where 12-6C (Carbon 12)serves as a reference point

the atomic mass of a chemical element is the mass of an atom at rest, most often expresses in atomic mass units (amu)
Periodic Law
1. The Periodic Law states that elements are arranged in order of increasing atomic number, elements with similar properties occur at periodic intervals.
2. when the elements are arranged in order of increasing atomic numbers, periodic recurrence of chemical and physical properties of the elements
Periodic Table
A Periodic Table is a graphical display of the elements in order of increasing atomic number in which elements with similar properties fall in the same column of the display.

elements within any given column of the periodic table exhibit similar chemical behavior
Period
is a horizontal row of elements in the periodic table
Group
1. is a vertical column of elements in the periodic table
2. elements within any given column of the periodic table exhibit similar chemical behavior
Alkali metal
1. is a general name for any element in Group IA (excluding Hydrogen)
2. they are soft shiny metals that readily react w/water
Alkaline earth metal
1. is a general name for any element in Group IIA
2. soft, shiny metal but only moderately react w/water
Noble gases
1. any element on far right of periodic table, group VIIIA
2. unreactive gases that undergo few if any chemical reactions
3. distinguishing electron in a (p) subshell, except for He
Halogen
1. general name for any element in Group VIIA
2. reactive elements that are gases at room temperature
metal
is an element that has the characteristic properties of luster, themal conductivity, electrical conductivity and malleability
nonmetal
is an element characterized by the absence of the properties of luster, themal conductivity, electrical conductivity and malleability
electron subshell
(L)/angular momentum quantum number = is an energy sublevel within an shell in which the electrons all have the same energy
2. distinguishs shapes of orbitals
3. identified by letters s,p,d,f,g, etc...
4. the number of subshells w/in a shell is the same as the shell number (ex. shell 1=1 sub, shell 2=2 sub)
5. subshell differ in size & energy
ex. apartments on one floor of apartment building
electron orbital
(m^L) m - subscript l (varies from -L to L)
1. a region of space where an electron with a specific energy is most likely to be found
2. distinguishes orientation (magnetic Quantum number)
3. accommodates a max of 2 electrons
ex. rooms within the apartment
s, p, d, f
subshell s = 2 electrons --> 1 orbital
subshell p = 6 electrons ---> 3 orbitals
subshell d = 10 electrons ---> 5 orbitals
subshell f = 14 electrons ---> 7 orbitals
electron spin
(m^s)
1. orientation of the spin of an electron (spin quantum number)
electron configuration
describes the orbitals that are occupied by the electrons in an atom
orbital diagram
is a notation that shows how many electrons an atom has in each of its occupied orbitals
Representative element
1. is an element located in the (s) area or the first 5 columns of the (p) area
2. distinguishing electron in a (s) or (p) subshell
transitional element
1. is an element located in the (d) area
2. distinguishing electron in a (d) subshell
inner transitional element
1. is an element located in the (f) area
2. distinguishing electron in a (f) subshell
electron shell
(n)/principle quantum number-main energy level = is the electron cloud around the atomic nucleus which contains approximately the same value of energy
--they have the same value of the principal quantum number "n"
--greater the n, greater the energy of the electron
physical properties
protons (a little bit neutrons
chemical properties
electrons - b/c they can be donated or accepted
atomic mass calculation
sum of fractional abundance X relative mass of each isotope
ex. 75.52/100 x 34.97 + 24.47/100 X 36.97
physical properties of Metal
electrical conductivity = high, decreases w/temp
thermal conductivity = high
luster = metallic gray or silver
physical state = almost all solids
malleability = can be hammered into sheets
ductile = can be drawn into wires
physical properties nonmetal
electrical conductivity = poor except graphite
thermal conductivity = good heat insulators except diamond
luster = non-metallic
physical state = solids, liquids & gas
malleability = brittle in solid state
ductile = non-ductile
formula for the max # of electrons in a shell
2n^2