development of the periodic table Flashcards

1
Q

what were elements arranged by in the 1800s?

A

atomic weight

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2
Q

who came up with their own table of the elements in 1869?

A

dimitri mendeleev

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3
Q

how did mendeleev arrange his table?

A

mostly in order of atomic weight, but switched elements if the properties meant it should be changed

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4
Q

why did mendeleev leave gaps?

A

for elements he thought hadn’t been discovered yet

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5
Q

what did newly discovered elements help to confirm?

A

that Mendeleev was correct as they fitted the pattern

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6
Q

what helped explain why the order of atomic weight was incorrect?

A

isotopes

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7
Q

describe the early periodic tables

A

incomplete with some elements placed in incorrect groups

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8
Q

similarities between newlands and mendeleevs table

A

-both arranged in order of atomic weight

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9
Q

how did newlands arrange the elements?

A

in octaves of 7

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10
Q

why was newlands work critiqued?

A

-some of his groups contained elements with no similar properties
-he mixed up metals and non-metals
-didn’t leave gaps for undiscovered elements

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11
Q

what did mendeleev do different to newlands?

A

left gaps

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