Atomic Structure Unit 4 Test

Question 1

Lavoisier

Answer 1

Helped to turn chemistry into an experimental science
Verified Law of Conservation of Mass
Beheaded

Question 2

Democritius

Answer 2

Greek professor
Suggested existence of atoms (named them atomos)
Came up with IDEA, had no proof

Question 3

John Dalton

Answer 3

Based his ideas on experiments

Created Dalton’s Atomic Theory

Question 4

Dalton’s Atomic Theory

Answer 4

1) All matter is composed of indivisible particles called atoms
2) Atoms do not change their identities when they undergo reactions
3) Elements have only one type of atom, all with the same properties. Elements of different atoms are different.
4) Compounds are composed of two or more elements combined in fixed proportions
5) Chemical reactions involve the rearrangement of atoms to give new compounds. Atoms are not created, destroyed, or broken down

Question 5

J.J. Thomson

Answer 5

Discovered the atom

Used Cathode Ray Tube to prove they existed

Question 6

Cathode Ray Tube

Answer 6

J.J. Thomson used it
Subatomic particles were attracted by a positively charged plate - therefore, had to be negative
This led to “plum pudding model”

Question 7

Plum Pudding Model

Answer 7

Entire atom is positive, with negative electrons randomly lodged in

Question 8

Rutherford

Answer 8

Trying to find experimental evidence to support plum pudding model
Shot alpha particles at a very thin layer of gold foil
Most particles went straight through, more than expected shot back and some deflected at an angle
Showed there was a dense center (nucleus) that’s positively charged

Question 9

Nuclear Atom

Answer 9

An atom with a dense center of positive charge around which tiny electrons moved in a space that was otherwise empty

Question 10

Goldstein

Answer 10

Discovered protons

Question 11

Chadwick

Answer 11

discovered neutrons

Question 12

Neutrons

Answer 12

Subatomic particle with no charge and slightly more mass than a proton
Location: nucleus

Question 13

Electrons

Answer 13

negative charge, location: cloud (outside nucleus)

Question 14

Protons

Answer 14

charge is positive, location: nucleus

Question 15

Atomic Number

Answer 15

number of protons in the nucleus of the atom

The atomic number identifies the element

Question 16

Atoms are electrically…

Answer 16

Neutral
# or protons = # of electrons

Question 17

Mass Number

Answer 17

of protons + # of neutrons in the nucleus of an atom

Question 18

Ion

Answer 18

A group of atoms that have a positive of negative charge

Has either gained or lost electrons

Question 19

Cation

Answer 19

positive ion that has has lost electrons

Question 20

Anion

Answer 20

negative ion that has gained electrons

Question 21

Bohr Model

Answer 21

Sought to explain electrons in more detail
Often called planetary model
Wrong, because we can’t predict location and path of electron

Question 22

of Electrons in Bohr Model

Answer 22

1st Energy Level: 2 electrons
2nd Energy Level: 8 electrons
3rd Energy Level: 18 electrons
4th Energy Level: 32 electrons

Question 23

Isotopes

Answer 23

atoms of the same element that differ in the number of neutrons in the nucleus
Because isotopes of an element have different numbers of neutrons, they have different mass numbers