3. atoms and molicules

Question 1

Question: Who was the Indian philosopher that first postulated the idea of the smallest particles of matter?

Answer 1

Maharishi Kanad

Question 2

Which of the following is a law established by Antoine L. Lavoisier related to chemical reactions?

Answer 2

Law of Conservation of Mass

Question 2

What name did Maharishi Kanad give to the smallest, indivisible particles of matter?

Answer 2

parmanu

Question 3

What does the Law of Conservation of Mass state?

Answer 3

Mass can neither be created nor destroyed in a chemical reaction.

Question 4

Question: Which of the following is NOT a postulate of Dalton’s atomic theory?

A) All atoms of a given element are identical in mass and properties.
B) Atoms cannot be created or destroyed in a chemical reaction.
C) Atoms of different elements can combine in simple whole-number ratios to form compounds.
D) Atoms can be subdivided into protons, neutrons, and electrons.

Answer 4

Atoms can be subdivided into protons, neutrons, and electrons.

Question 5

Question: Who is credited with the development of the atomic theory that suggested that matter is made up of tiny, indivisible particles called atoms?

Answer 5

John Dalton

Question 6

Which law states that in a chemical reaction, the total mass of the reactants is equal to the total mass of the products?

Answer 6

Law of Conservation of Mass

Question 7

What term is used to describe a substance that is made up of two or more different elements chemically combined in a fixed ratio?

Answer 7

Compound

Question 8

Which of the following particles are found inside the nucleus of an atom?

Answer 8

) Protons and neutrons

Question 9

What did Democritus and Leucippus call the smallest, indivisible particles of matter?

Answer 9

atom

Question 9

Which ancient Greek philosopher is known to have suggested the concept of indivisible particles called atoms?

Answer 9

Leucippus

Question 10

Which scientist laid the foundation of chemical sciences by establishing important laws of chemical combination?

Answer 10

Antoine L. Lavoisier

Question 11

Which other philosopher, apart from Maharishi Kanad, contributed to the idea of particles existing in a combined form?

Answer 11

Pakudha Katyayama

Question 12

Which law states that mass can neither be created nor destroyed in a chemical reaction?

Answer 12

Law of Conservation of Mass

Question 13

Which scientist proposed the ‘plum pudding model’ of the atom?

Answer 13

J.J. Thomson

Jolly jam in pudding

Question 14

According to the Law of Constant Proportions, the elements in a compound are always present in

Answer 14

Definite proportions by mass

Question 15

Who proposed the Law of Constant Proportions?

Answer 15

Joseph Proust

Question 16

In water (H₂O), what is the mass ratio of hydrogen to oxygen?

Answer 16

1:8

Question 17

Which scientist’s atomic theory explained the laws of chemical combination?

Answer 17

John Dalton

Question 18

According to Dalton’s atomic theory, atoms of a given element are:

Answer 18

Identical in mass and chemical properties

Question 19

What is the primary focus of Dalton’s atomic theory?

Answer 19

The nature of matter

Question 20

What modern techniques allow us to see atoms?

A) Optical microscopes
B) Electron microscopes
C) Scanning tunneling microscopy
D) Both B and C

Answer 20

D) Both B and C

Question 21

Atomic radius is measured in nanometres.
1/10 ^9 m =
1 m =

Answer 21

1/10 ^9 m = 1 nm
1 m = 10 ^9 nm

Question 22

From where were the names of many elements originally derived?

Answer 22

The names of the places where they were discovered

Question 23

What is the symbol for iron derived from?

Answer 23

Its Latin name ferrum

Question 23

What is the atomic mass unit now referred to as, according to the latest IUPAC recommendations?

Answer 23

u (unified mass)

Question 24

The atomic mass of which element is defined as equal to the mass of one carbon atom? atom?

Answer 24

Carbon

Question 25

What is a molecule that consists of two atoms called?

Answer 25

Diatomic

Question 26

Who proposed the atomic theory that stated that matter is made up of atoms that cannot be created or destroyed?

Answer 26

John Dalton

Question 27

What does the term “valency” refer to in chemistry?

Answer 27

The ability of an atom to bond with others.

Question 28

compounds in baking powder

Answer 28

Sodium, Hydrogen, Carbon, and Oxygen