elemental history -j.w. dobereiner - scanlon …...elemental history -j.w. dobereiner •german...
TRANSCRIPT
10/2/19
1
AIM• How is the periodic
table organized?
YOYO• Take today’s sheet• Answer question on top of
today’s note sheet
HOMEWORK• Element ID CER due tomorrow
10/4 (counts as a quiz)• Unit 1 HW Packet due Monday
10/7• 5-Min Element Quiz – Monday
10/7 (First 20 elements: name/symbol/number)
AGENDA• YOYO• Paint Chip Activity• History of PT notes
3
October
2018
Thursday
Paint Chip Activity
• You will be given a bag of 32 different color paint samples. As a team, organizethem as you see fit.• In the box on your note sheet, sketch how
you
Elemental History - J.W. Dobereiner
• German scientist grouped elements into triads, a set of three elements with similar properties (1829).• Chloride, Bromine, and Iodine Triad• Reacted easily with metals• The average of the atomic masses of
chlorine and iodine is very similar to that of iodine
• The downside – not all the known elements could be grouped into triads
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Elemental History - Dimitri Mendeleev
• Russian chemist and teacher, who published a table of elements in 1869• It showed the relationship between
over 60 elements• Elements were arranged in order of
atomic mass
Elemental History - Henry Mosley
• In 1931, British physicist Henry Moseley determined that each element had a specific number of protons• When Mendeleeve organized the
elements, the structure of the atoms was not yet known, as well as the fact that each element contained a specific number of protons
Elemental History – Present Day
• The modern periodic table is organized by increasing atomic number• Periods: refer to the rows• Each period corresponds to a principle energy level
• Groups/families: refer to the columns• Valence electrons correspond to each group (not including
transition metals)• Valence electrons – the outermost electrons• Look at the last number in the electron configuration
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3
Element Songs
• Elements in Order – Asap Science • https://www.youtube.com/watch?v=rz4Dd1I_fX0
• Daniel Radcliffe• https://www.youtube.com/watch?v=rSAaiYKF0cs
• The Elements• https://www.youtube.com/watch?v=zGM-wSKFBpo