3.Atoms and Molecules - I

Who postulated the idea of the smallest particles of matter called Parmanu?

• Democritus

• Leucippus

• Maharishi Kanad

• Pakudha Katyayama

What did Democritus call the indivisible particles of matter?

• Atoms

• Parmanu

• Elements

• Compounds

Who laid the foundation of chemical sciences by establishing the laws of chemical combination?

• Antoine L. Lavoisier

• Joseph L. Proust

• Democritus

• Leucippus

What is the law of conservation of mass?

• Mass can be created in a chemical reaction

• Mass can be destroyed in a chemical reaction

• Mass remains constant in a chemical reaction

• Mass changes randomly in a chemical reaction

What is the law of constant proportions also known as?

• Law of Conservation of Mass

• Law of Definite Proportions

• Dalton's Atomic Theory

• Law of Chemical Combination

Who provided the basic theory about the nature of matter and introduced the concept of atoms?

• Antoine L. Lavoisier

• Joseph L. Proust

• Democritus

• John Dalton

According to Dalton's atomic theory, atoms of a given element are ________ in mass and chemical properties.

• identical

• divisible

• random

• different

What is the modern day symbol for the element hydrogen?

• H

• He

• Hy

• Ho

What is the atomic radius measured in?

• Centimeters

• Millimeters

• Nanometers

• Kilometers

What is the name of the international scientific organization that approves names of elements, symbols, and units?

• IUPAC

• UNESCO

• WHO

• NASA