important figures and models

Question 1

Democritus what where his ideas.

Answer 1

1. All matter consists of invisible particles called atoms.
2. Atoms are indestructible.
3. Atoms are solid but invisible.
4. Atoms are homogeneous.
5. Atoms differ in size, shape, mass, position, and arrangement.
6. gaps between atoms or discontinuous.

• > Solids are made of small, pointy atoms.
• > Liquids are made of large, round atoms.
• > Oils are made of very fine, small atoms that can easily slip past each other.

Question 2

Aristotle what where his ideas.

Answer 2

1. did not believe in the atomic theory
2. all materials on Earth were not made of atoms.
3. elements of matter composed of Earth, Fire, Water, and Air.

Question 3

Alchemists what where their ideas.

Answer 3

1. they tried to turn led into gold.
2. they believed the four element theory ( Earth, Fire, Water, and Air ).
3. laid ground work for the experimental method.
4. they specified the nature of a few elements.

Question 4

John Dalton what where his ideas.

Answer 4

1. solid atoms of the same element are identical.
2. he defined the difference between a compound and an element.
3. He came up with the 1st periodic table.

Question 5

Thompson what where his ideas.

Answer 5

1. he discovered electrons.
2. electrons are tiny negatively charged particles.
3. Atoms are neutral .. so they contain a positive charge.
4. he developed the Plum Pudding model.

Question 6

Ernst Rutherford what where his ideas.

Answer 6

1. atoms have a positive, small dense nuclei.
2. electrons circle the nucleus.
3. atoms are mostly empty space.
4. planetary model.

Question 7

Niels Bohr what where his ideas.

Answer 7

1. electrons move in fixed energy levels called shells.
2. Bohr model.
3. more then 1 electron in an orbital.

Question 8

Chadwick what where his ideas.

Answer 8

1. Simplified atomic model.
2. proposed neutrons.
3. questioned why protons don’t fly apart in the nucleus !!!
   4.

Question 9

1) electron configuration?

2) electron rule?

Answer 9

1) 2 in the first shell and a limit of 8 in the continuing shells.
example: 2e-,8e-,8e-
2) electrons = protons

Question 10

Physical change?

Answer 10

1) the fundamental properties of an object do not change.
2) they can be easily undone

example: solid, liquid and gas

Question 11

Chemical change?

what are the 4 signs a chemical reaction has happened

Answer 11

1) changes at a molecular level.
2) new substance made as a result
3) outermost electrons take part in change
4) they are hard to revers
5) can create ions

                         4 signs 
1- change color
2- gas in evolved
3- solid being formed
4- heat being absorbed or released ( light )

Question 12

Nuclear changes?

Answer 12

1) occur in the nucleus of an atom
2) radioactivity is a spontaneous nuclear change called disintegration
3) actin ides and Po A+ and Rn undergo nuclear changes

Question 13

who discovered X-rays?

Answer 13

Wilhelm Rontgen

Question 14

who discovered Uranium?

Answer 14

Pierre and Marie Curie

Question 15

X-rays?

Answer 15

1) they are not emitted by radioactive materials.
2) light waves.
3) no charge
4) less penetrating then a gamma ray (stopped bye an in of lead).

Question 16

Types of radiation?

Answer 16

Wave radiation

Particle radiation

Question 17

Wave radiation?

Answer 17

Includes heat, light and UV

has no mass

Question 18

Particle radiation?

Answer 18

has mass or weight

Question 19

Ionizing radiation?

Answer 19

1) all types of radioactive ionize
2) they remove an electron
3) Gamma rays and X-rays can ionize matter.
4) ray transfers energy to an electron.
5) Particle radiation (Alpha, Beta) hits electrons knocking it of the atom.

Question 20

Radioactive Decay?

Answer 20

unstable atoms breaking down.

example: Alpha decay, Beta decay

Question 21

Half-life?

Answer 21

1) time it takes for half the atom to decay.
2) specific to each radioactive element.
3) the more radioactive an element the shorter its half-life.

Question 22

steps to find the Half-life?

Answer 22

1) find how many half-life’s have gone by.

2) x/2 times the number of half-life’s

Question 23

Artificial radiation?

Answer 23

occurs when the radioactive isotope is created in a bar

Question 24

Nuclear Fission?

Answer 24

1) splits the nucleus?

2) can be done by bombarding the nucleus with particles usually neutrons.

Question 25

Chain reaction?

Answer 25

only a few isotopes are fissionable.

radiation and energy being released

Question 26

Nuclear Fusion?

Answer 26

1) the combining of 2 nuclei into one.
2) requires high temperature and pressure.
3) releases a giant amount of energy.

Question 27

Mass defect?

Answer 27

1) the energy in a nuclear reaction comes from matter.
2) E = MC (squared)
3) mass number ≠ isotope mass ≠ mass of separate nucleons.
example: Carbon - 12

Question 28

How do Nuclear reaction work?

Answer 28

1) chain reactions
2) controlled chain reactions do not spread up.
3) a chain reaction is produced when 1 neutron is released during initial fission and is captured by a near by atom.

Question 29

How do you control a Chain Reaction?

Answer 29

1) less then critical mass = no reaction
2) critical mass = controlled reaction
3) more then critical mass = bomb

Question 30

Critical mass?

Answer 30

minimum amount of material needed to achieve critical mass

Question 31

the Atomic bomb ( A-bomb )?

Answer 31

1) bang 2 pieces of less then critical mass together.
2) create a critical mass.
3) uses fission.
4) has to be built a specific size.

———-produces—————

1) direct radiation
2) high temperatures
3) blast of air which carries contaminated dust
4) radioactive fallout

Question 32

The Hydrogen bomb ( H-bomb )?

Answer 32

1) uses fission, releasing 3.5 times more energy then fission.
2) requires 100,000,000 Celsius.
3) can be built to any size.

———————produces———————————–

• —- A-bomb to create heat
• —- then fission occurs.

1) direct radiation
2) high temperatures
3) blast of air which carries contaminated dust
4) radioactive fallout

Question 33

Electric power stations?

Answer 33

1) all work on the same principal

2) something turns a turbine, powering a machine (electricity or power)

Question 34

Hydroelectricity power stations?

Answer 34

————- benefits ————

1) renewable energy.
2) no air pollution.
3) no waste production.

————- disadvantages ——————

1) reservoirs drown large swathes of land.

Question 35

controversial Thermal power plant?

Answer 35

1) burning of fossil fuels produces steam to turn the turbine

2) non-renewable.
3) produces air pollution.

Question 36

Nuclear reaction?

Answer 36

fission

————————-advantage————————-

no air pollution

———————disadvantages——————–

1) non-nonrenewable
2) radioactive waste
3)

Question 37

Nuclear power plant 6 step by step?

Answer 37

1) fission reaction occurs in a generator, cadmium control rods to prevent a explosion or bomb.
* cadmium - absorbs neutrons and slows down chain reaction
2) heat from fission enters coolant.
3) coolant carries steam to generator ( which is filled with water )
4) steam turns turbine.
5) the turbine charges electricity into the generator.
6) steam is turn back into water,,,,,,,,then the hole cycle repeats

Question 38

Different reactors?

Answer 38

1) all reactors us fuel, moderators and coolant
2) what type they are depends on the country.
3) fuel is your gas
4) moderator slows down neutrons ( so they can react with the nuclei )
5) coolant carries heat away from the generator.
6) cadmium control rods control rate of change