Ch. 3 & 4 Concepts

Question 1

Thomson Model

Answer 1

Plum Pudding (negative particles in positive goo)

Question 2

Dalton Model

Answer 2

Billiard Ball (indivisible sphere)

Question 3

Rutherford Model

Answer 3

Nuclear (small dense area of positive charge w/ negative particles surrounding)

Question 4

Bohr Model

Answer 4

Planetary (electrons orbit nucleus in energy levels)

Question 5

Schrodinger Model

Answer 5

Quantum/Electron Cloud (electrons exist in orbitals, which are shapes where they are likely to be found)

Question 6

Thomson Experiment

Answer 6

Cathode Ray Tube (found that atoms had charges/electrons and protons)

Question 7

Rutherford Experiment

Answer 7

Gold Foil (shot positively charged alpha particles at gold foil, some alpha particles bounced off, found nucleus made of protons)

Question 8

Millikan Experiment

Answer 8

Oil Drop (found charge of electron is -1)

Question 9

mass defect

Answer 9

the amount of mass lost during the formation of a nucleus (more mass defect, more stable)

Question 10

binding energy

Answer 10

the energy that is converted from mass during the formation of a nucleus (more binding energy, more stable)

ΔE = Δmc^2

Question 11

Law of Multiple Proportions

Answer 11

When elements combine to make different compounds, the masses of the particles are always in ratios of small whole numbers in each compound (can have CO2 but not CO1.5)

Question 12

Law of Definite Proportions

Answer 12

Samples of a given compound always contain the same proportion of elements by mass

Question 13

20 or fewer protons in an atom

Answer 13

1:1 neutron to proton is most stable, too many neutrons = beta decay & not enough neutrons = electron capture/positron emission

Question 14

21-82 protons in an atom

Answer 14

1.5:1 neutron to proton is most stable, too many neutrons = beta decay & not enough neutrons = electron capture/positron emission

Question 15

83+ protons in an atom

Answer 15

inherently unstable, always alpha decay

Question 16

Any nuclear process that gets closer to the number of protons in iron will ______

Answer 16

release energy

Question 17

Any nuclear process that gets farther from the number of protons in iron will ______

Answer 17

absorb energy

Question 18

critical mass

Answer 18

minimum amount of mass needed for a sustained chain reaction

Question 19

What happens to the efficiency of a chain reaction when Uranium-238 and Uranium-235 nuclei are mixed?

Answer 19

the efficiency is lowered (some nuclei remain and do not undergo fission)

Question 20

How does efficiency affect critical mass?

Answer 20

the higher the efficiency, the lower the critical mass (less mass needed to sustain a chain reaction)

Question 21

Which is the most stable element?

Answer 21

iron

Question 22

ground state

Answer 22

n = 1, lowest energy level ring in Bohr’s planetary model

Question 23

“n” in Bohr’s model

Answer 23

the energy levels in Bohr’s planetary model (outer rings = higher number/more energy, inner rings = lower number/less energy)