Question 1:
Name the scientists that made the following discoveries:
(a) Classified elements into four groups according to their chemical properties, that is gases, non-metals, metals and metal oxides
(b) Proposed the Law of Octaves
(c) Constructed the triad groups consisting of three elements with similar chemical properties
Answer:
(a) Antoine Lavoisier
(b) John Newlands
(c) Johann W. Dobereiner
Name the scientists that made the following discoveries:
(a) Classified elements into four groups according to their chemical properties, that is gases, non-metals, metals and metal oxides
(b) Proposed the Law of Octaves
(c) Constructed the triad groups consisting of three elements with similar chemical properties
Answer:
(a) Antoine Lavoisier
(b) John Newlands
(c) Johann W. Dobereiner
Question 2:
In the historical development of the Periodic Table of Elements, Moseley arranged the elements in ascending order of proton numbers. However, before the modern Periodic Table of Elements was used, scientists made their own discoveries. Compare how Dobereiner and Newlands arranged the elements in the Periodic Table of Elements before Moseley.
Answer:
Difference:
Dobereiner grouped three elements having the same average mass and named them triads. All three elements in a triad were found to have the same chemical properties. His classification showed the relationship between the chemical properties of elements with atomic mass.
Newlands arranged elements in order of increasing atomic mass. He arranged seven elements in a row because he found that the chemical and physical properties of the first element repeats for every eighth element. He names this arrangement as Octave Law.
Similarity:
Both relate atomic mass with chemical properties.
In the historical development of the Periodic Table of Elements, Moseley arranged the elements in ascending order of proton numbers. However, before the modern Periodic Table of Elements was used, scientists made their own discoveries. Compare how Dobereiner and Newlands arranged the elements in the Periodic Table of Elements before Moseley.
Answer:
Difference:
Dobereiner grouped three elements having the same average mass and named them triads. All three elements in a triad were found to have the same chemical properties. His classification showed the relationship between the chemical properties of elements with atomic mass.
Newlands arranged elements in order of increasing atomic mass. He arranged seven elements in a row because he found that the chemical and physical properties of the first element repeats for every eighth element. He names this arrangement as Octave Law.
Similarity:
Both relate atomic mass with chemical properties.