Unit 2- Composition of Matter

Question 1

Democritus (460 -370 BC)

Answer 1

Discreteness Theory
-Limit to which matter is broken.
-Believed in existence of atoms.
-Matter is discrete.

Question 2

Aristotle (384-322 BC)

Answer 2

Continuous Theory
-Matter is infinitely divisible.
-Rejected the idea of atoms.
- Believed that atoms were made from natural elements of water, fire, earth and air.

Question 3

T/F

Protons and electrons have approximately the same mass.

Answer 3

False

Protons and neutrons have approximately the same mass.

They are about 1800 times bigger than an electron.

Question 4

Most of the mass of an atom is in its ___________.

Answer 4

Nucleus

Question 5

Most of the volume of an atom is occupied by its __________.

Answer 5

Electrons

Question 6

Define:

Subatomic particle

Answer 6

A very small particle that is a building block for atoms.

Question 7

T/F

An atom has infinite/indefinite number of protons, neutrons and electrons.

Answer 7

False

It has a definite number of subatomic particles.

Question 8

Proton:
- Location:
- Actual Mass:
- Relative Mass:
- Relative Charge:

Answer 8

• Nucleus
• 1.673x10^-24
• ~1
• +1

Question 9

Electron:
- Location:
- Actual Mass:
- Relative Mass:
- Relative Charge:

Answer 9

• Outside nucleus (shell)
• 9.109x10^-28
• ~0
• -1

Question 10

Neutron:
- Location:
- Actual Mass:
- Relative Mass:
- Actual Charge:
- Relative Charge:

Answer 10

• Nucleus
• 1.675x10^-24
• ~1
• 0
• 0

Question 11

T/F

All atoms can be identified by the number of protons and electrons they contain.

Answer 11

True