Chemistry #3

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35 terms · chemistry #3

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

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