The student will:
identify parts of periodic chart
explain periodic law in relationship with
chemical reactions
calculate trends of periodic chart
calculate trends according to location of
element on periodic chart
Chapter 5
p.123
Periodic Table
Periodic means =
Repeating pattern
Dimitri Mendeleev
Russian chemist,
1866, published in 1869
Mendeleev-
discovered pattern by chemical properties---left empty spaces…
42 yrs later …
Henry Mosely English chemist 1911
Modern definition of Atomic# = modern organization of Periodic Table.
• PT divided into two sections
• Metals / non-metals via stair steps
• Metals on the left of stairs
• Metals conduct electricity & heat
• Non-metals on the right of stairs
• Non-metals do not conduct electricity very well
and heat only slightly. Most are gases and
powders.
• Metalloids
• Elements touching the stair steps
» Exclude Aluminum
• Properties of both, “can’t make up their mind”
• “Semi-conductors” ….used in computer chips
•
•
•
•
Elements going sideways period
Elements going down group or family
Period numbers down side tell largest occupied energy level.
Group numbers across the top tell number of valence electrons.
• there are some deviations
• transition elements, the group # equal the sum of the s & d electrons.
*
Important Concept
Periodic Law ::::::
Groups or families exhibit same characteristics.
• Note:
outer valence electrons determine chemical properties
SO…..all elements in a group or family will have similar chemical
properties.
The physical & chemical
properties of elements are a periodic
function of their atomic number.
• Official way to say it :
• Group 1 Alkali Metals
» Very reactive, explosive, does not exist
pure in nature
• Group 2 Alkaline-Earth Metals
» Very reactive but not as active as group
1 does not exist pure in nature
• Group 3-12 Transition Metals
» Less reactive, some not reactive, good
conductors of electricity, heat
Group 17 Halogens
Very reactive, gases
Group 18 Noble Gases Not reactive, inert,
Lanthanides
Extremely similar, tedious to
distinction
Actinides
Radioactive, short life
• Group 1:
s block
“Alkali Metals”
all elements in group 1 have 1 valence ehence… all have similar properties.
Extremely reactive…..explosive
Not found in pure state in nature
Combines vigorously with non-metals
Usually stored under kerosene
Going down group lower melting point
Li
Na
K
Rb
Cs
Fr
HYDROGEN :
doesn’t share same properties as group 1
is placed above group 1 because it does have
the 1s1 orbital filled.
• Group 2
Alkaline-Earth Metals s2 block
harder, denser, stronger
too reactive to be found in purity in nature
Be …
Mg…
Ca…
Sr…
Ba…
emeralds….green fireworks
white fireworks, very hard,
Ca3PO4 = bones ,
CaCO3 = Concrete , Marble, limestone
Chlorophyll in plants is calcium based
Red fireworks
Medicine tracking, white chalky stuff people drink, isotopes
“ With a color pencil lightly color in groups 1 & 2 to
color code the s block on your periodic block”
• Transitional Metals
groups 3-12
color code
in each case the sum of outer s electrons and d electrons = group number
• Fe, Co, Ni, = make steel, only these can make a magnet
• Al = most abundant metal on earth
• Fe = second abundant, most used #1
• Group 11
• Cu
• Ag
• Au = coinage metals, nonreactive ,can be pure on earth.
Group 12
Zn = used in plating… ZnO
Cd = rechargeable batteries
Hg = poisonous, accumulates in bodies, thermometers
• Non-metals
»
»
»
»
»
color code entire p block
begin to fill p sublevel
# of valence electrons = group# -10
Most are gases @ room temp
1 non-metal is a liquid at room temp = Br
Poor conductors of electricity and heat
• Group 17 = Halogens
• F…
most chemically reactive
Use to etch glass and tooth decay
• Cl …
• Br …
• I…
disinfective …. Swimming pools
lipstick, dyes
thyroid medicine, purple vapor
» Sublimination: solid
gas
» CO2: solid
gas “never gets wet, never a liquid”
• Diatomic Molecules =
• 2 atoms of same element chemically combine in nature
N2
O2 F2 Cl2 Br2 I2
H2
When writing these you must write them as diatomic !!!!!
Or it will be wrong!!!!
Noble Gases:
group 18… inert ….filled energy orbital
Laser Light shows, Neon lights
Carbon
3 forms called allotropes p. 626 in book
**Allotrope= same element different structural form
l.
Diamond….. Atoms in a pyramid
2. Graphite ….. Atoms in layers. pencil
3. Coal………….Atoms in a sphere…Fullerene
4. A fourth has been invented ….. carbonite
periodic table based on carbon-12
Silicon
sand, SiO2 ….. Glass, computer chips
Nitrogen
each breath is 80% N2, diatomic, fertilizers,
TNT, dynamite
• Phosphorus
» Fertilizers, Match heads
• Antimony & Bismuth
» Added to other metals to lower melting point
» Automatic fire sprinkler
• Oxygen
» 20% of air , diatomic, 2 allotropes
» Ozone, O3 ….. How made ?????
• Alloys:
– Brass = Cu + Zn
– Bronze = Cu + Sn
– Sterling Silver = Cu + Ag
– Pewter = Cu + Sn + Sb
• Gold:
•
•
•
•
100% gold = 24 karat
92% gold = 22 karat….8% copper
58% gold = 14 karat …42% copper
50% gold = 12 karat ….50% copper
• What property does copper add to the gold?
• What makes your skin turn green with fake gold?
The student will:
identify parts of periodic chart
explain periodic law in relationship with
chemical reactions
calculate trends of periodic chart
calculate trends according to location of
element on periodic chart