Bridging Class: Lesson 1 (Chemical History)

Question 1

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

Answer 1

Democritus

Question 2

He proposed his atomic theory which explains that (1) Each element is made up of atoms;
(2) Atoms of a given element are identical;
(3) Compounds are formed when atoms combine with each other;
(4) Chemical reactions involve reorganization of the atoms.

Answer 2

John Dalton

Question 3

In 1869, he created the periodic table and discovered that the properties of elements were periodic functions of their atomic weights.

Answer 3

Dmitri Mendeleev

Question 4

He proposed the theory of electromagnetism and made the connection between light and electromagnetic waves.

Answer 4

James Clark Maxwell

Question 5

He proposed that electricity was made of discrete negative particles he called electrons.

Answer 5

George Stoney

Question 6

He made experiments with cathode ray tubes, demonstrating that cathode rays have a negative charge.

Answer 6

Sir William Crooke

Question 7

He used cathode ray tubes to study canal rays which had electrical and magnetic properties opposite of an electron.

Answer 7

Eugene Goldstein

Question 8

He discovered that certain chemicals glowed when exposed to cathode rays. He named these X-rays.

Answer 8

Wilhelm Roentgen

Question 9

He discovered radiation by studying the effects of X-rays on photographic film.

Answer 9

Henri Becquerel

Question 10

He used cathode ray tubes to determine the charge to mass ration of an electron.

Answer 10

Sir Joseph John Thomson

Question 11

He discovered alpha, beta and gamma rays in radiation.

Answer 11

Ernest Rutherford

Question 12

They theorized that radioactive particles cause atoms to break down releasing radiation that takes the form of energy and subatomic particles. They discovered the radioactive elements polonium and radium.

Answer 12

Pierre and Marie Curie

Question 13

He proposed the idea of quantization to explain how a hot, glowing object emitted light.

Answer 13

Max Planck

Question 14

He discovered that there appeared to be more than one element at each position on the periodic table. The term isotope was coined by Margaret Todd as a suitable name for these elements.

Answer 14

Frederick Soddy

Question 15

He created the theories of relativity and hypothesized about the particle nature of light.

Answer 15

Albert Einstein

Question 15

He found that noble gases have stable electron configurations.

Answer 15

Richard Abegg

Question 16

He invented a device that detect alpha particles.

Answer 16

Hans Geiger

Question 17

He determined the charge of an electron through his oil drop experiment.

Answer 17

Robert Millikan

Question 18

He performed the alpha particle experiment and established that the nucleus was very dense, very small, and positively charged.

Answer 18

Ernest Rutherford

Question 19

He discovered that the number of protons in an element determines its atomic number.

Answer 19

Henry Moseley

Question 20

He developed the Bohr atomic model, with electrons travelling in orbits around the nucleus.

Answer 20

Neils Bohr

Question 21

He proposed that electrons have a wave-particle duality.

Answer 21

Louis de Broglie

Question 22

He developed the Schrodinger equation which describes how the quantum state of a system changes with time.

Answer 22

Erwin Schrodinger

Question 23

What do you call the atomic model proposed by John Dalton that all matter is composed of atoms?

Answer 23

Dalton’s Billiard Ball Model

Question 24

In this model, the atom is made up of negative electrons that float in a sphere or raisins in a fruit cake.

Answer 24

Thomson’s Plum Pudding Model

Question 25

He called electrons as corpuscles

Answer 25

John Joseph Thomson

Question 26

This model was a result of the well-known gold foil experiment where most of the alpha particles went through the foil, but a few were deflected. Rutherford demonstrated that the atom has a tiny, heavy nucleus.

Answer 26

Rutherford’s Nuclear Model

Question 27

This model depicts atoms as small, positively charged nuclei surrounded by electrons in circular orbits.

Answer 27

Bohr’s Planetary Model

Question 27

He postulated that the angular momentum of the electrons is quantized, it can only have discrete values.

Answer 27

Neils Bohr

Question 27

He proposed the Law of Triads, wherein the middle element in certain triads had an atomic weight that was the average of the other two members.

Answer 27

Johann Dobereiner

Question 28

He proposed the Law of Octaves, when the elements are aligned according to their atomic weight, every eight element shares similar properties.

Answer 28

John Newlands

Question 28

He recognized the repeating pattern or the periodic behavior among elements.

Answer 28

Lothar Meyer

Question 29

He studied the relationship of the atomic volume and the relative atomic mass of 28 elements.

Answer 29

Lothar Meyer

Question 30

He formulated the periodic law. The properties of the elements are periodic functions of their atomic masses.

Answer 30

Dmitri Mendeleev