TOIPC: Periodic Table Organization
Do Now: From your activity yesterday, and p.5 answer page 6 in your packet
Periodic Law
• There is a periodic repetition of chemical and physical properties of elements when arranged by increasing atomic numberincreasing atomic number
What is the periodic table?
• compact way of organizing elements• contains a lot of information • allows us to make predictions about
behaviour and properties of elements
• Elements
The periodic table hasn’t always look like this
History of the Periodic Table
• End of the 1700’s – less than 30 elements known
• Many elements discovered during 1800’s
• Many experiments done to determine atomic masses
John Newlands
• 1864: if elements arranged by atomic mass - properties repeat every 8th element
• Law of Octaves – did not work for all known elements
• Key idea was correct: Properties of elements do repeat in periodic way
Mendeleev & MeyerMendeleev produced 1st accepted PT: 1869•Elements ordered by ↑ atomic mass into columns with similar properties•PredictedPredicted existence & properties of undiscovered elements•Not totally correct
– more accurate atomic mass calculations showed some elements weren’t in right place
Remember
1860’s:
•No subatomic particles yet discovered
•Dalton’s billiard ball model of the atom
1913 – Henry Moseley
• by 1913, protons & electrons discovered– Neutrons were predicted
• Moseley determined atoms of each element contain unique # protons (= atomic number)
• rearranged Mendeleev’s PT by atomic number instead of mass
• problems with elements in wrong place disappeared
Periodic Table is arranged according atomic number and organized into groups and periods
COLUMNSGroups/Family numbering (1 18) left to right
TELL US NUMBER OF VALENCE ELECTRONS (KIND OF)
Valence Electrons – electrons in the outer shell
• Chemical behaviour determined by # valence electrons
• Elements with same # valence electrons will have similar chemical properties
–Elements in same column have similar chemical properties
Going Down Column 1:Going Down Column 1:
2-8-18-32-18-8-1Fr7
2-8-18-18-8-1Cs6
2-8-18-8-1Rb5
2-8-8-1K4
2-8-1Na3
2-1Li2
1H1
ConfigurationElementPeriod
Valence Electrons
414 or IVA
313 or IIIA
22 or IIA
11 or IA
Number of Valence Electrons
Group
COLUMNS• Aka groupsgroups or familiesfamilies
– #1 thru 18, Arabic numerals– (old way, Roman Numerals and letters)– - tell us number of valance electrons
• (KIND OF) = works for 1,2, 13,14,15,16,17,18
CO LUMN
Turn to packet page one, lets label the columns and valence electrons
Names of Families(AKA group A elements)
• Group 1 = Alkali Metals
• Group 2 = Alkaline Earth Metals
• Groups 3-12: Transition metals
• Group 17 = Halogens
• Group 18 = Noble Gases
Transition Metals (in yellow)
• Groups 3 through 12
form brightly colored salts
Glenn Seaborg: 1950’sf-Block Metals
• Lanthanide (rare Earth metals) – can be found naturally on Earth, only 1 is radioactive
• Actinide– all are radioactive, some are made in the lab. INCLUDES Uranium
Turn to packet page one, lets label the the f-block
metals
ROWSPeriod numbering (1 7) top to bottom
TELL US NUMBER OF SHELLS (energy levels)
Energy Levels = Row Number• Elements in same row
have same # of principal energy levels
ROWS
• Rows are called seriesseries or periodsperiods– #1 thru 7- TELL US HOW MANY ENERGY LEVELS
ROW
Turn to packet page one, lets label the periods