Chp 5 History of the Periodic Table

Question 1

Greeks

Answer 1

Four elements: Air, earth, water and fire

Question 2

Robert Boyle

Answer 2

First to define the term element - Simple substance and compound was a combination of elements

Question 3

Humphrey Davy

Answer 3

Passing electric current through salts can isolate the elements
Increase number of element known

Question 4

Dobereiner

Answer 4

Found Triads
Groups of three elements with similar chemical properties, the middle element’s atomic weight being half-way between the other two.

Question 5

Newlands

Answer 5

The Law of Octaves
Periodic repetition of chemical properties when elements were put in order of atomic weight. Every eighth element had similar properties
(Noble gas haven’t been discovered)

Question 6

Mendeleev

Answer 6

Found law of octaves by placing the elements in order of atomic weight, their chemical and physical properties repeated periodically - Periodic Law

Question 7

Mendeleevs’s Periodic table’s Law

Answer 7

1. Elements with similar chemical properties in vertical columns called Groups
2. Iodine and tellurium out of atomic weight order to accommodate their properties
3. Left gaps for elements that were not yet discovered

Question 8

Moseley

Answer 8

Used x-rays to find the number of protons in atoms of each element and arranged the periodic table with atomic number