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chem-- periodic table


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orginized periodic table by atomic mass
organized periodic table by atomic number
periodic law
similiarities in elements are the result of the number of outermost valence electrons
how much of the periodic table is metal
small section called metalloids
elements with both metallic and non matallic properties
(B, Si, Ge, As, Sb, Te, Po)

*Po = raidoactive
all elements with atom numbers greater than 83 are...
raidoactive isotopes
as you move left ---> to right you go from
Metal---> to metalloid ---> to non metal
18 of them
vertical columns of elements with similar properties because they have the same number of valence electrons
AKA "Family"
group 1
alkali metals
- most raidoactive mentals
- do not exist free in nature
- hydrogen although in group 1 is NOT an alkali metal
Group 2
alkali earth metals
- very raidoactive metals
- do not exist free in nature
Group 13
- Boron = metalloid
- {Al - Te} Metals
group 14
*Carbon* has allotropes
any element which can exist in more than one form
group 15
contains nitrogen-- tripple bond
- tripple bond makes nitrogen almost unreactive
group 16
- contains oxygen-- double bond
- double bond makes oxygen somewhat unreactive
oxygen- allotropes
has 2 allotropes

1= O2 (Gas)
2= O3 (gas) = ozone
group 17
* most reactive non-metals
* do not exist free in nature
- contains (4) of the (7) HOFBrINCl2 --diatomic molecules

H²- (g)
O²- (g)
F²- (g)
I²- (s)
N²- (g)
Group 18
noble/ inert gases
- monoatomic molecules
-some rare Xe & Kr compounds do exist
(He, Ne, Ar, Kr, Xe, Rn)
7 of them
horizontal rows of elements
transition metals
groups 3-11
periods 4-7
- some what unreactive metals
- some transition metals can form colored solutions or solids (C4 = Blue)
lanthanide series
(period 6) (57-71)(Can be found naturally on earth)

Rare earth elements or
inner-transition elements

* only one element in the series is raidoactive*
actinide series
(period 7) (89-103)
- all are raidoactive
- not found in nature
either single uppercase letter of an uppercase letter with and lowercase letter
- credited with the discovery of the atomic nucleus
rutherford's gold (Au) foil experiment
rutherford "bombarded" a think gold foil with (alpha)particles which are positivly charged
What does it mean??:
many particles moved passed the gold foil
the atom is mostly EMPTY space
What does it mean??:
some of the (+)alpha particles deflected back off the foil
the Nucleus of an atom is (+) charged and that most of the mass of an atom is in the nucleus
planets revolve around the sun like _____ revolves around the _____
ELECTRONS revolves around the NUCLEUS
negative particle that is found OUTSIDE ther nucleus and has a mass of zero
AKA: Nuclide or Nucleons

Protons and neutrons
symbol: P= :H (each . = 1)
charge: +1
Mass: 1g
Location: inside nucleus
symbol: n= ;1 (.=1 ,=0)
charge: +1
Location: inside nucleus
symbol: eˉ¹= ;e =ß
(.=1 ,=0)(ß= beta)
charge: -1
Mass: 0
Location: outside nucleus
atomic number of protons
never changes
neutral atom
# of particles = # of electrons
an atom with an electron charge
(+) Ion
AKA: Cation
- an atom that has lost electrons
(-) Ion
AKA: Anion
- an atom that has gained electrons
protons + neutrons =
mass number
symbol formate
top left corner = mass #
top right corned = charge
middle = element symbol
bottom left = atomic number
an atom with the same number of protons (atomic #) but a different number of neutrons (mass #)and thus a different mass
Mass Number
atomic mass
the weighted average, by mass of all know isotopes for a given element
atomic mass is based on...
the relative % abundance of each isotope in the element
atomic mass unit (amu)
a unit of mass based on the carbon- 12 isotope = 12.000 amu

* 1 amu = 1/12th mass of carbon-12 *
atomic mass formula
atomic mass= (% abundance)(mass of isotope) + (% abundance)(mass of isotope)
Boron has (2) isotopes.
B-10 has a mass of 10.013 amu and % abundance of 19.9% B-11 has a mass of 11.0093 amu and a % abundance of 80.1%what is the atomic mass of boron?
atomic mass= (% abundance)(mass of isotope) + (% abundance)(mass of isotope)

X = (.199)(10.013) + (.801)(11.0093)

X= 1.9925 + 8.8184

Atomic mass = 10.8109
another name for nucleus
natural radioactivity
The spontaneous (decay) disintegration of “unstable” nuclei to “mere stable” nuclei through a transmutation of one element into another.
one element change into another by releasing a sub atomic particle or proton of radiant energy
why does transmutation occur?
each radioactive isotope seeks to have a neutron proton ration of about 1:1 (n:p)
lead block test
separation of particles by magnetic and electric fields
natural radioactive decay: General form
A ---> B + C

A= unstable radioisotope
B= stable isotope
C= subatomic particle
law of conservation of charge and mass
in nuclear process BOTH charge and mass are conserved
Alpha decay
releases an alpha particle

*mass # goes down by 4 and atomic # goes down by 2*
name the types of natural radioactive decay
1- general
2- alpha
3- beta +
4- beta -
during alpha decay what is the change, if any, in mass # and/or Atomic #?
Mass #- goes DOWN 4
Atomic # goes DOWN 2
beta (-) decay
releases a ß- = -1 e
(Beta negative = electron)
during Beta (-) decay what is the change, if any, in mass # and/or Atomic #?
Mass #- remains the same
Atomic #- goes UP by 1
Beta (+) decay
releases the positron
during Beta (+) decay what is the change, if any, in mass # and/or Atomic #?
Mass #- remains the same
Atomic #- goes DOWN 1
artificial transmutation
(General form- formula)
General form:
A+B --> C+D

A= target nucleus
B= bombarding particles
C= new isotope
D= subatomic particles
artifical transmutation
rediaisotopes are made in a lab when a target nucleus is bombarded with a high energy particle (proton, electron, neutron, positron)
Particle accelerator
mechines that speed up CHARGED particles so theat they can penetrate the target nucleus (series of electromagnetic fields)
HALF LIFE of radioactive material
the time it takes for a radioactive substance to decay to 1/2 its original mass
does the half life ever change?
NO!!! the half life NEVER changes- its uneffected by temperature, pressure or volume
half life periods =
total time
----------- (over)
1/2 life
use of radioisotopes
1- chemical tracers : C-12
2- Medicine- short 1/2 life so that it will leave the body quickly
3- industry- to radiate food, to preserve it
4- geology/ archaeology- C-14/ U-238 ~ fossil dating
definition of Nuclear Energy
the conversion of a small amount of mass into radiant energy
nuclear energy
~the starting materials (reactants) lose some mass and produce products that are more stable and lighter

~Enormous amounts of energy are produced
eintein called this the "Mass defect"
E= MC²

E= energy
M= mass
C= speed of light
the two processes of nuclear energy
nuclear fission and nuclear fusion
definition of fission recations
the "splitting" of HEAVY atomic nuclei into smaller, more stable "fission- fragments" and the release of a lot of energy
process of fission reactions
neutrons are "captured" by a target nucleus breaking a LARGE nucleus into smaller isotopes
fission reactions result in
1- energy
2- more radioisotopes
3- more neutrons
what is fission used for
to produce electricity, radioisotopes used in medicein, and industry/research
benefits of nuclear fission
A- efficient source of energy without the air pollution associated with the burning of fossil fuels
B- produces useful radioisotopes used in medicine and research
Problems with nuclear fission
A- Meltdown/Nuclear accident
B- coolant H2O is returned to its source over-heated killing fish and other animals
C- the productiton of toxic raidoactive waste with long 1/2 lifes
fission fuel cells
Pu-239 (breeder reactor)

** U-238, which comprises more than 99% of all natural Uranium is NOT fissionable fuel**
raidoactive waste with cause by fission
its a problem becaus of its long 1/2 life and storage issues
nuclear fusion
the joining of (2) "light nuclei" to form a more stable and heavier nucleus
nuclear fusion ________ energy compared to nuclear fission
~*Produces greater*~

nuclear fusion PRODUCES GREATER energy compared to nuclear fission
why is it difficult for fusion to occur?
A- b/c of the (+) charge of the small nuclei, a strong repulsive force exists between the nuclei making it difficult for them to react
how do you make fusion happen?
you need high temperatures
AKA: thermonuclear reactions
benefits of fusion
could provide an unlimited source of energy without the pollution associated with the burning of fossil fuels and nuclear fission

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