UNIT 5 – Periodic Laws

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# UNIT 5 – Periodic Laws - PowerPoint PPT Presentation

UNIT 5 – Periodic Laws. THE PERIODIC CHART. H ISTORY. Dalton : grouped elements by their properties Berzelius : gave elements names and symbols ( important because he established order) Newlands law of the octaves 1 st and 8 th counted on his chart were similar

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### UNIT 5 – Periodic Laws

THE PERIODIC CHART

HISTORY
• Dalton: grouped elements by their properties
• Berzelius: gave elements names and symbols

( important because he established order)

Newlands law of the octaves 1st and 8th counted on his chart were similar

Doberiener developed groups of 3’s called triads, had math rule mass of 1st plus mass of 3rd divided by 2 = mass of 2nd

Meyer: graphed elements by masses

Mendeleyev: University professor in Russia, he published the Periodic Chart of elements on March 9, 1869 similar to ours. He developed the groups and series with only 7 major “families”.
• Ramsey: In the 1890’s the 8th family was discovered
• Moseley: grouped chart by the order of

• Joliet: produced the 1st synthetic element in 1936, Tc
• IUPAC: A committee that take care of our present chart ( meet every other year in Paris )
Parts
• Families (8) named columns
• Groups (18) numbered columns
• Series / Periods (8) numbered rows
FAMILY NAMES
• ALKALI - NITROGEN
• ALKALINE - CHALCOGEN
• “NO NAME”(transition) - HALOGEN
• CARBON - INERT (NOBLE)
Regions of the Chart
• Active Metals “s” first and second groups of elements
• Transition “d” groups 3 – 12 metals
• “p” elements of groups 13 – 18 metals / metalloids / nonmetals
• Rare Earth “f” Rare natural metals and synthetic elements
The Steps
• Metals To the left of the steps (zig-zag)
• Metalloids On / near the steps
• Nonmetals To the right of the steps
Periodic Properties

1. Atom Size

• a) down - family or group increases , add new layers of electrons ( shells/energy levels)
• b) to right - is smaller, protons have stronger pull

Fr is the largest

F is the smallest

2. Ion Size

• a) Metals who lose electrons are called cations M+

M+ is smaller than M atom

• b) Nonmetals gain electrons are called anions Nm-

Nm- is larger than Nm atoms

• 8th family normally does not form ions
3. Activity
• a)Groups/families of metals are down more active
• b) Groups/Families of Nm up is more active
• c) Across ( period/series )

more active-------------- less------------ more active

4 Metallic Properties
• increase as going down
• increase at left
5 Ionization Energy (IE)
• The Energy needed to remove one electron from an element

1st IE 2nd IE 3rd IE 4th IE

Least Energy More E Somewhat more Most E

• easy: this depends on the #of valence electrons Metals have a LOW IE
• hard: on inner shells, once valence are gone Nonmetals have HIGH IE

6 Electron Affinity (EA)

• the attraction of an element for its outer shell electron

Metals have a LOW EA / Nonmetals have HIGH EA

7 Electronegativity (EN)

• the energy exchange as a an atom gains one electron

Metals have a LOW EN/ Nonmetals have HIGH EN

Glitch: where a family or group doesn’t fit a pattern, the most common

glitch is 13 group, but groups 2-3, 8, 10 and 15 sometimes break the rules