the periodic table. review all atoms of a specific element are alike all atoms of different elements...
TRANSCRIPT
The Periodic TableThe Periodic Table
REVIEWREVIEW
All atoms of a specific element are alikeAll atoms of different elements are different90 naturally occurringArranged on Periodic Table to show trends
A Brief History of the A Brief History of the Periodic TablePeriodic Table
Mendeleev – Moseley - Seaborg
Mendeleev (1869)Mendeleev (1869)Thought pattern must exist between all elementsOrganized table by...ATOMIC MASS
Elements in columns show similar properties…Both physical and chemical!
Predicted properties of “missing” elements
MendeleevMendeleev’’s s TABLETABLE
His notesHis notes
What he thought!What he thought!“I began to look about and write down the elements with their atomic weights and typical properties, analogous elements and like atomic weights on separate cards, and this soon convinced me that the properties of elements are in periodic dependence upon their atomic weights.”
Mendeleev, Principles of Chemistry, 1905, Vol. II as quoted at <http://www.aip.org/history/curie/periodic.htm>.
DefinitionDefinition
What does PERIODIC mean? A repeating pattern
Mendeleev left some spaces in his table because not all elements lined up according to atomic mass. He used info he knew about surrounding elements to PREDICT properties and masses of unknown elements.
How about that!
MendeleevMendeleev’’s Predictions vs. s Predictions vs. Actual Properties of Element Actual Properties of Element
# 32# 32 “Ekasilicon” Germanium
Date 1871 (predicted)
1886 (discovered)
Atomic Mass
72 72.6
Density 5.5 g/cm3 5.47 g/cm3
Bonding power
4 4
Color Dark gray Grayish-white
Moseley (c. 1914)Moseley (c. 1914)rearranged table by ...ATOMIC NUMBERdetermined atomic number of elements by using x-rays to determine number of protons in element
MoseleyMoseley’’s s workwork
Seaborg (1944)Seaborg (1944)
rearranged Periodic Table with...Lanthanide and Actinide Series
pulled out/separated from main Periodic Table
discovered 10 new elements & countless isotopes
3D3DAlexanderAlexander’’s s
Arrangement of Arrangement of ElementsElements
definitiondefinition
Periodic LawThe physical and chemical properties of the elements are periodic functions of their atomic number
definitiondefinition
Octet RuleThe tendency of atoms to gain or lose electrons so they acquire eight electrons in their outer energy level
Numbered 1 – 18Group numbers tell us the number of electrons in that element’s outer energy level - the number in redElements within the same family have similar but not identical properties
1 2
13
141516
17
18
Columns of Table = Columns of Table = groupsgroups or or familiesfamilies
definitiondefinitionValence electronselectrons found in the outermost energy level
use the group number (the number in red) to determine number of valence electrons
NAMES to KnowNAMES to Know
NAMES to KnowNAMES to Know
Group 1Alkali Metals
NAMES to KnowNAMES to Know
Group 2Alkaline Earth
Metals
NAMES to KnowNAMES to Know
Groups 3-12Transition
Metals
NAMES to KnowNAMES to Know
Inner Transition Metals:Lanthanide
SeriesActinide Series
NAMES to KnowNAMES to Know
Group 16Chalocgens
NAMES to KnowNAMES to Know
Group 17Halogens
NAMES to KnowNAMES to Know
Group 18Noble Gases
Rows of Table = Rows of Table = periodsperiods
7 periodsPeriod = # of energy shells in atomProperties are not alike within a period:across each period (row), the chemical
& physical properties of elements change
these properties are repeated in the next period (the row below)
7654321
Periods 1 to 7Periods 1 to 7
Regions of the Periodic Regions of the Periodic TableTable
Metals - to the left of the stair-step lineNon-Metals - to the right of the stair-step lineMetalloids - along the stair-step line
Regions of the tableRegions of the table
METALS
METALLOIDS
NONMETALS
One more!
MetalsMetalsFound to LEFT of zigzag line on tableGood conductors of heat & electricityMalleableDuctileHigh melting pointsShinyTend to lose electrons forming cations
NonmetalsNonmetalsFound to RIGHT of zigzag line on tablePlus Hydrogen (atomic number = 1)Poor conductors of heat & electricityBrittle when solidDullLow melting pointsTend to gain electrons forming anions
MetalloidsMetalloidsaka Semi Metalsaka Semi Metals
Found along both sides of zigzag lineProperties of both metals & nonmetalsOkay conductors of heat & electricityShiny or dull