C2 The Periodic Table Flashcards
(14 cards)
Who is the person that made the biggest breakthrough in the history of the periodic table?
Dimitri Mendeleev
What did Dimitri Mendeleev do?
- He first arranged the elements in order of Atomic Weight
- But he also left gaps for elements of which he thought had not be discovered yet
- he went as far as to predict many elements in the periodic table now
- and he also switched the order of elements based on atomic weight in order to match the pattern
When did Dimitri Mendeleev make his discovery?
Mid 19th century
Who came up with the idea of Triads?
Döbereine
What is Döbereine’s triads?
- similar chemical properties often occurred in threes, these are called triads
What were Newland’s octaves?
- he arranged elements in the order of increasing atomic weight, and he noticed that every 8th element reacted in a similar way - law of octaves
Who came up with the octave idea?
Newland
What did Dimitri Mendeleev do?
He developed the first modern periodic table
How did Dimitri Mendeleev arrange the elements in the periodic table?
He arranged the elements in order of increasing atomic weight, and he also switch the arranged of some elements to match the properties of other elements in that group, he also left gaps for which he thought of elements which had not been discovered yet - and predicted many of these.
What is the problem with ordering elements in order of atomic weight?
The problem is that elements can appear in the wrong order due to the presence of isotopes, this is why the modern periodic table has been arranged in atomic number.
What is an example of ordering the elements with increasing atomic weight but is wrong?
Tellurium and Iodine
What is the formula for Ammonium hydroxide?
NH4^4+ OH^-
What does Diatomic mean?
2 Atoms per Molecule
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