Chemical History

Question 1

He postulated that all matter is made up of small destructive units called atoms

Answer 1

Democritus

Question 2

Proposed the idea of quantization to explain how glowing object emitted lights

Answer 2

Max Planck

Question 3

Proposed that each element is made up of atom and that the atoms of the same elements are identical

Answer 3

John Dalton

Question 4

Proposed that compounds are formed when atoms combine each other

Answer 4

John Dalton

Question 5

Proposed that chemical reaction involves reorganization of atoms

Answer 5

John Dalton

Question 6

_____ discovered that there appeared to be more than one element at each position on the periodic table. ____ then coined these elements as isotope.

Answer 6

Frederick Soddy, Margaret Todd

Question 7

Periodic table in increasing atomic weights

Answer 7

Dmitri Mendeleev

Question 8

Found that noble gases have stable electron configuration

Answer 8

Richard Abegg

Question 9

Propsed theory of electromagnetism

Answer 9

James Clerk Maxwell

Question 10

Created theories of relativity and hypothesized the particle nature of light

Answer 10

Albert Einstein

Question 11

Proposed that electricity is made of electrons

Answer 11

George Stoney

Question 12

Created a device that can detect alpha particles

Answer 12

Hans Greiger

Question 13

Made experiments with cathode rays determining it’s negative charge

Answer 13

Sir William Crooke

Question 14

Determined charge of electron through oil drop experiment

Answer 14

Robert Milikan

Question 15

Performed alpha particle experiment and established that nucleus is small dense and positively charged

Answer 15

Ernest Rutherford

Question 16

Performed alpha particle experiment and established that nucleus is small dense and positively charged

Answer 16

Ernest Rutherford

Question 17

Discovered X-rays

Answer 17

Wilhelm Roentgen

Question 18

Discovered that the number of protons in an element determines it’s atomic number

Answer 18

Henry Moseley

Question 19

Discovered radiation

Answer 19

Henri Becquerel

Question 20

Determined charge to mass ratio of electron using cathode ray tubes

Answer 20

Sir Joseph John Thomson

Question 21

Proposed that electrons have wave-particle duality

Answer 21

Louis de Broglie

Question 22

Discovered alpha, beta and gamma rays in radiation

Answer 22

Ernest Rutherford

Question 23

Theorized that radioactive particles causes atom to release radiation in the form of energy and subatomic particles.

Answer 23

Pierre and Marie Curie

Question 24

Discovered radioactive element polonium and radium

Answer 24

Pierre and Marie Curie

Question 25

Proposed Law of triads. “Middle elementsof certain triads have an atomic weight that was the average of other two”

Answer 25

Johann Dobereiner

Question 26

Proposed Law of Octaves. “When elements are aligned according to thei atomic weight, every eighth element shares similar properties

Answer 26

John Newlands

Question 27

Recognized repeating pattern among elements

Answer 27

Lothar Meyer

Question 28

Periodic table of elements in increasing atomic number

Answer 28

Henry Moseley