HAHSHAH

Question 1

Who is credited with first formalizing a particle theory of matter?

Answer 1

Democritus

A Greek philosopher around 400 BC.

Question 2

What term did Democritus use to describe indivisible particles?

Answer 2

Atoms

From the Greek term ‘atomos’, meaning indivisible.

Question 3

List the six points of Democritus’ atomic theory.

Answer 3

• Atoms are particles in the void
• Atoms are always in motion
• Atoms are indivisible
• Atoms come in different sizes and shapes
• Atoms make life predictable
• The human soul is made of soul atoms

Question 4

Which influential thinkers dismissed the idea of atoms after Democritus?

Answer 4

Plato and Aristotle

Their dismissal led to the concept of the atom being forgotten for almost 2200 years.

Question 5

In what year did John Dalton re-establish atomic theory?

Answer 5

1808

He was a teacher from England.

Question 6

What law did Dalton explain using his atomic theory?

Answer 6

The law of conservation of mass

He utilized the laws of definite and multiple proportions.

Question 7

List the main points of Dalton’s atomic theory.

Answer 7

• All matter is composed of small particles called atoms
• Atoms of the same element are identical
• Atoms from different elements differ in size, mass, and properties
• Atoms cannot be divided, created, or destroyed
• Atoms of different elements combine in small whole-number ratios to form compounds
• In chemical reactions, atoms are combined, separated, or rearranged

Question 8

What experiments were conducted by scientists like J. J. Thomson in 1897?

Answer 8

Experiments with cathode ray tubes

These tubes glowed when subjected to high voltages.

Question 9

What did the glow in cathode ray tubes consist of?

Answer 9

Particles streaming from the negative terminal to the positive

This was a key discovery in understanding atomic structure.

Question 10

True or False: The particles in cathode ray tubes could push objects.

Answer 10

True

Question 11

What effect did a magnetic field have on the particles in cathode ray tubes?

Answer 11

The particles were deflected by a magnetic field

Question 12

Fill in the blank: Atoms of different elements combine in small whole-number ratios to form _______.

Answer 12

Compounds

Question 13

Fill in the blank: Atoms cannot be ______, created, or destroyed.

Answer 13

Divided