PERIODIC TABLE OF ELEMENTS

Question 1

• Wrote the first extensive list containing 33 elements

- Distinguished between metals and non-metals

Answer 1

Antoine Lavoisier (1743 - 1797)

Question 2

• Developed a table of atomic weights

- Introduce letters to symbolize elements

Answer 2

Jöns Jakob Berzelius (1779-1848)

Question 3

• He classified some elements into group of three, which he called triads. (Law of Triads)
• The elements in triad has similar chemical properties and orderly physical
  properties.

Answer 3

Johann Wolfgang Dobereiner (1780-1849)

Question 4

Suggested that elements be arranged in “octaves” because he
noticed (after arranging elements in order of increasing atomic
mass) that certain properties repeated every 8th element

Answer 4

John A. R. Newlands (1837 – 1898)

Question 5

• He is considered to be the “Father of Modern Periodic Table”
• Produced a table based on atomic mass but arranged “ periodically ” with
  elements with similar properties grouped together.
• Gaps were left for elements that were unknown at
  that time and their properties predicted
• Periodic Law (1869) – “The chemical and
  physical properties of elements are periodic
  functions of their atomic numbers.”

Answer 5

Dmitri Mendeleev (1834 – 1907)

Question 6

discovery of the atomic number refined the way elements are listed in the periodic table. Prior to his discovery, the elements were listed by atomic mass.

Answer 6

Henry Moseley