Atomic Stucture

Question 1

Radius of an atom

Answer 1

1 x 10(-10)

Question 2

What charge is the nucleus

Answer 2

Positive

Question 3

Nucleus surrounded by

Answer 3

Negative charged electrons

Question 4

Protons have a charge of

Answer 4

+1

Question 5

Electrons have a charge of

Answer 5

-1

Question 6

Atoms have the same number of

Answer 6

Protons and electrons so no overall charge

Question 7

Most of the mass is in the

Answer 7

Nucleus

Question 8

Radius of nucleus is less than

Answer 8

1/10000 of the atoms radius

Question 9

The electrons are arranged

Answer 9

Different distances from the nucleus in different energy levels

Question 10

The energy of an electron may change when

Answer 10

The atom emits or absorbs electromagnetic radiation

Question 11

Absorbing electromagnetic radiation

Answer 11

Moves electron to a higher energy level further fr m the nucleus

Question 12

Electromagnetic radiation is emitted when

Answer 12

An electron drops a lower energy level

Question 13

When an atom loses and outer electron

Answer 13

It become a positive ion

Question 14

When an atom gains an outer electron

Answer 14

it becomes a negative ion

Question 15

All atoms of an element have the same number of

Answer 15

Protons

Question 16

No. of protons is called

Answer 16

atomic numbers

Question 17

Mas number is

Answer 17

Total number of protons and neutrons

Question 18

Can have a different number of neutrons called

Answer 18

Isotope

Question 19

Plum pudding model(5)

Answer 19

Tiny sphere 
Couldn’t be divided
JJ Thompson in 1897
Ball of positive charge
Electrons embedded in it

Question 20

1905 Rutherford and mars den

Answer 20

Bombarded thin gold foil with alpha particles

Question 21

Most particles passed through

Answer 21

But some didn’t

Question 22

Some particles were deflected so

Answer 22

Must have come close to a concentration of charge

Question 23

Conclusion of the Rutherford and mars den experiment

Answer 23

Mass is concentrated in a central nucleus which was positively charged
Electrons surround the nucleus

Question 24

Niels Bohr

Answer 24

Electrons orbit the nucleus at specific distances

Question 25

James Chadwick 1932

Answer 25

Other experiments | Neutron in the nucleus

Question 26

Some atomic nuclei are unstable and

Answer 26

Give out radiation in order to become more stable

Question 27

The type of radiation emitted depends on

Answer 27

Why the nucleus is unstable and is a random process

Question 28

The activity of a radioactive source is

Answer 28

The rate at which it decays

Question 29

The rate at which it decays is measured in

Answer 29

Becquerels

Question 30

One becquerel is equivalent to

Answer 30

One decay per second

Question 31

The count rate is

Answer 31

The number of decays recorded each second by a detector | Geiger-Muller tube

Question 32

One becquerel is equivalent to

Answer 32

One count per second

Question 33

Three main types of radiation

Answer 33

Alpha Beta Gamma

Question 34

Most ionising is

Answer 34

Alpha

Question 35

Least ionising is

Answer 35

Gamma

Question 36

Alpha

Answer 36

``` Two neutrons Two protons Ejected form the nucleus Easily absorbed Cause damage passing though living cells ```

Question 37

Beta

Answer 37

High speed electron Elected from the nucleus as a neutron and turns into a proton Likely to cause damage if absorbed by living cells Can penetrate the body and inner organs

Question 38

Gamma

Answer 38

Electromagnetic radiation Emitted form the nucleus Pass through the living cells without being absorbed or causing ionisation

Question 39

The fourth type of radiation

Answer 39

A neutron

Question 40

Radiation contamination is

Answer 40

The unwanted presence of materials containing radioactive atoms

Question 41

The hazard front the contamination is due to

Answer 41

The decay of the contaminating atoms

Question 42

The type of radiation emitted affects

Answer 42

The hazard

Question 43

Irradiation

Answer 43

The process of exposing an object to nuclear radiation Can be deliberate or accidental Doesn’t make objets radioactive

Question 44

Protecting against irradiation

Answer 44

Sources of low activity for short times

Question 45

Half life is

Answer 45

The time It takes for half the nuclei to decay Or The time it takes the count rate, or activity of a sample containing the isotope to fall to 50% of its original value

Question 46

The half doesn’t change

Answer 46

Different isotopes have different half lives

Question 47

Isotopes with a short half life

Answer 47

Unstable Emit radiation quickly Hazardous Not radioactive for long

Question 48

Isotopes with a long half life

Answer 48

More stable Radioactive for long time Emit radiation slowly Less hazardous

Question 49

Medical trace ( nuclear radiation)

Answer 49

Radioactive isotuoe ingested | Travels around body and van be detected in the outside

Question 50

When using an isotope for medical reasons it is important to

Answer 50

Use the right half life, activity and type of radiation

Question 51

Best tracer would be

Answer 51

Gamma Can penetrate the body They are leat ionising

Question 52

When is ther background radiation

Answer 52

Al the time

Question 53

Level of background reaction depends on

Answer 53

Location | Occupation

Question 54

What is nuclear fission

Answer 54

Splitting of a large unstable nucleus | Unstable nucleus absorbs a neutron

Question 55

During fission

Answer 55

Splits into two smaller nuclei Emits two or theee neutrons Gamma ray and energy

Question 56

All the products of fission have

Answer 56

Kinetic energg

Question 57

Neutrons emitted start a

Answer 57

Chain reaction by being absorbed by other large unstable nuclei

Question 58

Nuclear weapon is

Answer 58

Result of an uncontrolled chain reaction

Question 59

During nuclear fusion

Answer 59

Two light nuclei join to form a heavier nucleus Some of the mass is converted into energy Some energy emitted as radiation

Question 60

Nuclear equations represent

Answer 60

Radioactive decay

Question 61

Alpha particle is represents by

Answer 61

4 He 2

Question 62

A beta particle is represented by

Answer 62

0 e -1

Question 63

When an alpha particle I emitted

Answer 63

Mass number is reduced by 4 | Atomic number is reduced by 2

Question 64

Beta decay

Answer 64

Mass number does not change | Atomic number increased by 1