Chapter 6-7
The Periodic Table, Periodic Law,
and The Elements
Periodic Table
• Elements are
arranged in increasing
atomic number
according to similar
properties in columns
or groups
• It was developed over
decades
• 1790’s- Lavoisier
compiled a list with 23
elements
John Newland
• 1864- arranged
elements by the “law
of octaves”
• (1st arranged) – right
idea but not exactly
right after the first 14
or so.
Demitri Mendeleev (1834-1907)
• Russian
• 1869- designed the
“modern table”
Moseley slightly
rearranged based on
atomic number and
created our basic modern
table
Periodic Law
• There is a periodic repetition of properties
when arranged by atomic number
Groups
• Also called families
(vertical columns)
• Share similar
properties
– End in same econfiguration
– Same valence e– Same reactivity
Period
• Horizontal rows
• Share same highest
energy level
Periodic trends
• Atomic radius- half the distance between the
nuclei of identical atoms that are bound
together
– Group trend: increase down
Atomic radius increases down because as you go down
there are more electrons and more energy levels and
with each energy level you get further from the nucleus.
– Periodic trend: decrease left to right
Atomic radius decreases from left to right because when
you go across a period electrons are being added to the
same energy level, which makes a stronger attraction
and pulls electrons closer to the nucleus resulting in a
smaller atom.
Ionic radius
• Ion- has a charge (+ or -) – when an atom
gains or loses an e• Cation- positive ion- lost e- - smaller than
neutral
• Anion- negative ion- gained e- - larger
than neutral
*** same trend as atomic radius
Ionization energy
•
•
•
•
•
•
Energy required to remove an eEach e- has its own energy
1st IE<2nd<3rd
Group trend: decreases down
Period trend: increases across
These trends are both due to the fact that
electrons are more difficult to remove from
stable elements
Electron affinity
• Energy change that
occurs when an e- is
acquired by a neutral
atom
• Fe + e-  Fe-
Electronegativity
• Relative ability of an atom to attract electrons to itself in a
bond
– Pauling electronegativity scale
– Period: increase left to right
– Group: decreases down
– General trend: increase up
and right
F=most electronegative
O=second most
Fr=least
Hydrogen and helium
• Unique- can both
occupy 2 groups
• H= 1A & 7A
• He= 2A & 8A
• 99% of Universe
• 76% = H
• 23% = He
Alkali Metals: groups 1 or 1A
• Alkali comes from Arabic“ashes”
• All are very reactive, react
violently with H2O, soft, low
density, low melting pts.
• Li- batteries, dehumidifiers,
bipolar disorder medication
• Li2CO3 -in glass, airplane parts
• Na- salt, vapor lamps, heat
exchanger in nuclear reactors,
electrolyte
• K- electrolyte for muscles, one
of 3 main ingredients in
fertilizer
– KNO3 in large scale
fireworks and gun powder
Alkaline Earth metals: group 2 or
2A
• All but Be form oxides that will not
melt and form basic solutions
• Less reactive than 1A
• More dense, higher melting points
• Be- with Al, Si, and O makes beryl
(emerald/ aquamarine), moderates
neutrons in reactors, Be/Cu alloys
are used for tools where no sparks
can be formed like refineries
• Mg- backpack frames, bicycle
wheels, “mag” wheels, oxide used to
line furnaces, every chlorophyll has
1 Mg+2, muscle function and
metabolism- found in “hard” H20 with
Ca +2
Alkaline earth metals continued…
• Sr- crimson fireworks
• Ba- paints, additive in
glass, diagnostic tool
in medicine
• Ra- highly
radioactive, once
used in glow in the
dark paint for watches
Aluminum Group: group 13 or IIIA
• B- metalloid, Borax is the name of the mined compound
• B/Si/O=borosilicate=pyrex
• Mined in the Mojave Desert
Boric acid: disinfectant, ant repellant
Boron nitride: second
hardest substance
Aluminum group continued….
• Al- cans, foil
• most abundant metal on
earth
• 3rd most abundant element
on earth
• Mined from bauxite
– Strengthens ceramics, heatresistant fabric, ruby and
sapphires are mainly Al2O3
– Al2(SO4)3- alumantiperspirant and water
purification
Al group Continued…..
• Ga- used in some
thermometers from 30o to
2400oC
– Gallium arsenide produce
photoelectric cells
– Solar power=calculators
– 10x more efficient than Si
chips
– Gallium nitride- used for blue
lasers (can triple storage)
Carbon group: group 14 or IVA
• C- has its own studyorganics
– Exist in at least 4
natural forms –
diamond, graphite,
coal (soot),
Buckminster fullerene
Carbon group Continued…..
• Si- computer chips,
solar cells, 2nd most
abundant element in
the crust, most
common form is
silica, (Si02) A.K.A
sand, glass, quartz
– Silicon carbideindustrial abrasive
(carborundum)
Carbon group Continued….
• Ge- metalloid- solid
state electronics
• Pb- toxic, was in
paint, may have been
1st pure metal,
additive in glass,
causes brain damage
• Sn- coating for cans,
Bronze, construction
materials, foil
Nitrogen Group: Group 15 or VA
• N- colorless, odorless, unreactive-=
80% of air; compounds- fertilizer,
explosives (TNT), DNA, Ammonia
(cleaning), dyes, nitroglycerin
– HNO3- used to etch metal plates
and other industrial uses
Nitrogen group continued..
• P- has 3 allotropes (white, red, black),
phosphoric acid, processed cheese,
laxatives, matchbox, baking powder,
fertilizer, ATP, DNA, detergents
Nitrogen continued…
• As- toxic, Arsenic sulfide was used
as medicine, metalloid
• Sb- antimony sulfide was used as
a cosmetic to darken eyebrows
and make eyes appear larger, 5%
of modern Pb storage batteries,
Sn/Sb alloy can be molded
(tableware)- metalloid
Nitrogen Continued….
• Bi- Pepto Bismol,
Bi/Pb/Sn/Cd alloy
called woods metal
used as a plug in
sprinkler system
Oxygen Group: group 16 or IVA
• O- 2 allotropes 02/03--most abundant
element on earth
-bleaching agent
50% of earth crust=
20% of air
Oxygen Continued…
• S- 10 allotropes
-Cinnabar, galena
-can be found in nature in
pure form (yellow)
H2S04= fertilizer production,
steel, paper, paint
silver tarnish is H2S +
AgAg2S
Oxygen continued…
• Se- works with Vitamin E to
prevent cell damage, can be
toxic= RDA= 10 mg, toxic L050=
200 m/m3, can convert light to
electricity- used in solar panels,
photographer meters,
photocopiers, semiconductors
• Te- metalloid- semiconductorsrare
• Po- named for Poland- rare,
radioactive, toxic
Halogens: Group 17 or VIIA
• Most reactive
nonmetals- “halo”salt “genero”- form=
salt formers
• State of matter at
room temp.
• F, Cl= gas
• Br= liquid
• I, (At)= solid
Halogens continued….
• F- most
electronegative
element- most active
element
– “fluere”- latin, “to flow”added to H20 and
toothpaste to prevent
decay, teflon= F/C
compound reacts with
U to form gases (U
enrichment) U-235
Halogens Continued…
• Cl- deadly gas in its pure form
-can be a disinfectant
-NaCl=bleach
-nerve blocker in medicine
HCl- removes rust or algae, etc. (muriatic)
-mixed with oil=PVC
(Poly Vinyl Chloride)
Halogens Continued…
• Br- photographic film
• I- photographic film, needed to maintain a
healthy thyroid (controls growth and
metabolic rate), disinfectant, iodized salt
• At- radioactive, man-made
Nobel Gases: group 18 or VIIIA
• All were considered
inert (nonreactive)
until the 1960’s
• He, Ne, Rn- still no
compounds
Noble gases continued…
• He- used in balloons,
blimps, and dive
tanks
-liquid form=coolant
-superconducting magnets
-pale yellow “neon” lights
• Ne- first “neon” light
-bright orange
Noble gases continued…
• Ar- insulation in windows, 1% of air,
blue “neon” light, atmosphere of
incandescent lights, high temp.
welding
• Kr- used as insulation in windows
• Xe- 1st to form a compound
• Rn- deadly radioactive gas from U
decay, found under homes
Transition metals
• D-block- groups 3-12 – B
elements
• Various uses and forms
-Cobalt 60=chemotherapy
-Fe= construction
-Fe, Co, Ni= magnets
-Ag, Au, Pt= “precious” metals
-Cu= wire
-Co= red blood cells
-Mn= cell respiration
Inner transition metals
• The “f” block
• Lanthanide and actinide series
• Ce= used to remove C from
steel, movie projectors, search
lights
• Pu= 239 reactor fuel
• Am= smoke detectors
• Nb, Pr= welding goggles
• Yb, Eu= TV screens, computer
monitors