the periodic table. review all atoms of a specific element are alike all atoms of different elements...

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