Unit B | Topic 3 | Atoms / Laws, theories, observations

Question 1

Who was the first person to ever theorize “the atom”?

Answer 1

Democritus:
Described the smallest particles as “atomos”, meaning “indivisible”

Question 2

Who was Aristotle and what did he contribute to the study of atoms?

Answer 2

• A Greek philosopher who opposed Democritus
• Stated that everything is made of either earth, fire, water, or air.

Question 3

How long was Aristotle’s theory on the atom taken as fact for?

Answer 3

2000 years

Question 4

Definition of:
Alchemist

Answer 4

Someone who was part magician and part scientist (around pre 1500’s)

Question 5

The study of Alchemy is also known as:

Answer 5

Pseudo-science

Question 6

What did alchemists in the pre 1500’s seek out to perform?

Answer 6

Turn any metal into gold, but they were not interested in truly understanding matter

Question 7

What did Robert Boyle contribute to the study of matter?

Answer 7

• Realized that elements form compounds
• Believed that the purpose of chemistry was to determine the kinds of particles in any substance

Question 8

What did Sir Francis Bacon contribute to the study of matter? (And what time frame?)

Answer 8

Proposed that science should be based on experimental evidence instead of thoughts or ideas (1500’s)

Question 9

What did Antoine Lavoisier contribute to the study of matter?

Answer 9

• Known as the “father of modern chemistry”
• Discovered 23 pure elements
• He was very careful with experiments and kept organization over research and data
• Created the law of conservation of mass

Question 10

Definition of:
Law of conservation of mass

Answer 10

In a chemical change, the total mass of a new substance is the same as the total mass of the original.

Question 11

Definition of:
Law of definite composition

Answer 11

Compounds are pure substances that contain two or more elements that are always in fixed proportions

Question 12

Example of:
Law of definite composition

Answer 12

Water (H2O) will always contain 2 Hydrogen and 1 Oxygen

Question 13

What was Dalton’s Atomic theory?

Answer 13

• All matter is made up of atoms
• Atoms can’t be created, destroyed, or divided
• All atoms of the same element are the same in mass and size

Question 14

Definition of:
Law (in science)

Answer 14

An action or condition that has been observed so constantly that scientists are convinced it will always happen

Question 15

Definition of:
Theory

Answer 15

An explanation of an event that has been supported by consistent results and is accepted by a majority of scientists

Question 16

Definition of:
Model

Answer 16

A mental image used to help explain an event

Question 17

Definition of:
Observation

Answer 17

The use of senses to gather informtation

Question 18

What did J J Thompson discover and contribute to chemistry?

Answer 18

• Created the “plum pudding” model (kinda looks like a cookie though)
• Discovered and named negatively charged particles (electrons)
• Reasoned that there must be positively charged particles (protons)

Question 19

What did Rutherford discover and contribute to chemistry?

Answer 19

• Most of an atoms mass is in the center (nucleus)
• Named the positively charged particles Protons
• Theorized that neutrally charged particles, called neutrons, exist

Question 20

What did Bohr discover and contribute to chemistry?

Answer 20

• Pictured an atom as a “solar system”
• Electrons rotate around the nucleus
• Stated that electrons are found in fixed pathways called orbits

Question 21

What does the “cloud” atomic model theorize?

Answer 21

Electrons have levels but there’s a “cloud” around the nucleus where they’re most likely found

Question 22

What are all atoms made of?

Answer 22

3 subatomic particles

Question 23

What are the three subatomic particles?

Answer 23

• Protons
• Neutrons
• Electrons

Question 24

Where are Protons and neutrons found in an atom?

Answer 24

The nucleus

Question 25

Where are Electrons found in an atom?

Answer 25

Electron shells (orbits)

Question 26

What charge do Protons have

Answer 26

A positive charge
(P for positive)

Question 27

What charge do Electrons have?

Answer 27

A negative charge

Question 28

What charge do Neutrons have?

Answer 28

None (the are neutral)
(N for neutral)

Question 29

Together, what do both Protons and neutrons make up?

Answer 29

The atomic nucleus

Question 30

In a Bohr diagram, what does the top number represent?

Answer 30

The amount of Protons (and electrons) in an atom

Question 31

True or False:
Neutral atoms have a different number or protons and electrons

Answer 31

False:
Neutral atoms, since they’re neutral, have the same amount of protons and electrons

Question 32

In a Bohr diagram, what do the large letter(s) represent?

Answer 32

A name of a certain element

Question 33

How do you determine how many “rings” an atom has?

Answer 33

The row number of that specific atom

Question 34

How do you determine how many electrons can be contained in a certain ring?

Answer 34

The number that is located under the group (column) the element is located in

Question 35

How many electrons can each shell hold?

Answer 35

1st shell: 2
2nd shell: 8
3rd shell: 8
4th shell: 18
5th shell: 18
6th shell: 32
7th shell: 32

Question 36

Definition of:
Valence Electrons

Answer 36

The electrons on the outer most ring of an atom that can react with other atoms

Question 37

Definition of:
Anions

Answer 37

Negatively charged ions (they have more electrons than protons)

Question 38

Definition of:
Cations

Answer 38

Positively charged ions (they have less electrons than protons)

Question 39

Why do atoms attempt to gain or lose electrons?

Answer 39

To have a full shell of valence electrons