P4 Atomic Structure

Question 1

Define atom

Answer 1

The smallest part of an element that can exist.

Question 2

All substances are made up of…?

Answer 2

atoms

Question 3

The radius of an atom is …?

Answer 3

0.1 nm (1 x 1010 m)

Question 4

The overall charge on an atom is…

Answer 4

zero/neutral

Question 5

Define element

Answer 5

Contains only one type of atom

Question 6

Substances found in the periodic table are…?

Answer 6

elements

Question 7

Approximately how many elements are there?

Answer 7

100

Question 8

Define isotope

Answer 8

An atom of the same element with different numbers of neutrons

Question 9

Define radioactive decay

Answer 9

An unstable nucleus changes to become more stabe and gives out radiation

Question 10

We cannot predict when a given atom will decay, this means that radioactive deacy is ….?

Answer 10

randon

Question 11

Define activity

Answer 11

Rate at which decay occurs

Question 12

What are the units of activity?

Answer 12

Becquerels (Bq)

Question 13

Define count rate

Answer 13

Number of decays recorded each second by a Geiger-Muller tube

Question 14

Defne half life

Answer 14

The time taken for number of radioactive nuclei in a sample to halve OR time taken for count rate (or activity) from a sample to fall to half its initial value

Question 15

Define contamination

Answer 15

The unwanted presence of materials containing radioactive atoms

Question 16

Define irradiation

Answer 16

When an object is exposed to radiation

Question 17

Does an irradiatied object become radioactive itself?

Answer 17

no

Question 18

The process of radiation removing electrons from atoms to form ions is called…?

Answer 18

ionisation

Question 19

If ionisation happens in DNA it can cause ___________ which may result in ____________

Answer 19

mutations, cancer

Question 20

Define peer review

Answer 20

Checking of scientific results by other scientific experts

Question 21

Define mass number

Answer 21

The total number of protons and neutrons in an atom

Question 22

Define atomic number

Answer 22

The number of protons in an atom (number of electrons is the same in a neutral atom)

Question 23

Electrons in atoms are located in ___________

Answer 23

energy levels

Question 24

Absorption of radiation by an atom may result in ____________ moving to a ________________ energy level

Answer 24

electrons, higher

Question 25

Emission of radiation from an atom may lead to _____________ moving to a ______________ energy level

Answer 25

electrons, lower

Question 26

Who came up with the Plumb Pudding model of the atom

Answer 26

J J Thompson

Question 27

Describe the Plumb Pudding model of the atom

Answer 27

A ball of positive charge with negative electrons embedded in it

Question 28

Was the Plumb Pudding model correct?

Answer 28

no

Question 29

What experiment did Rutherford do?

Answer 29

Alpha particle scattering

Question 30

What did Rutherford's experiment reveal?

Answer 30

Atoms have a central area of positive charge with electrons surrounding it

Question 31

Who discovered that electrons are located in energy levels?

Answer 31

Niels Bohr

Question 32

What did Jame Chadwick discover about the atom?

Answer 32

That the nucleus contains neutrons as well as protons

Question 33

What did John Dalton contribute to our understanding of atomic theory?

Answer 33

Matter is made up of descrete, spherical particles, known as atoms

Question 34

Name the three subatomic particles

Answer 34

proton, neutron, electron

Question 35

Which particles are located in the atoms nucleus

Answer 35

protons, neutrons

Question 36

What is the charge of each subatomic particle?

Answer 36

proton +1, neutron 0, electron -1

Question 37

What is the mass of each subatomic particle?

Answer 37

proton 1, neutron 1, elecrton ≈ 0

Question 38

Name the three types of radiation

Answer 38

alpha, beta and gamma

Question 39

What is an alpha particle?

Answer 39

two protons and two neutrons

Question 40

What is a beta particle?

Answer 40

an electron

Question 41

What is gamma radiation?

Answer 41

electromagnetic wave (NOT a particle)

Question 42

What is the range of alpha radiation in air?

Answer 42

short - 5 cm in air

Question 43

What is the range of gamma radiation in air?

Answer 43

unlimited in air

Question 44

What's the range of beta radiation in air?

Answer 44

medium - about 1 m

Question 45

What will absorb (stop) alpha radiation?

Answer 45

paper/skin

Question 46

What will absorb (stop) beta radiation?

Answer 46

about 5 mm aluminium

Question 47

What will absorb (stop) gamma radiation?

Answer 47

several centimetres of lead

Question 48

What is the ionising power of alpha radiation?

Answer 48

very high

Question 49

What is the ionising power of beta radiation?

Answer 49

medium

Question 50

What is the ionising power of gamma radiation?

Answer 50

low

Question 51

What is meant by the ionising power of radiation?

Answer 51

how likely it is to ionise atoms which it comes into contact with

Question 52

How does alpha decay alter the mass number of the parent nucleus?

Answer 52

decreases by 4

Question 53

How does alpha decay alter the atomic number of the parent nucleus?

Answer 53

decreases by 2

Question 54

How does beta decay alter the mass number of the parent nucleus?

Answer 54

stays the same

Question 55

How does beta decay alter the atomic number of the parent nucleus?

Answer 55

increases by 1

Question 56

How does gamma radiation alter the mass and atomic number of the parent nucleus

Answer 56

unchanged (energy is released as the particles in the nucleus reorganise to a lower energy arrangement)