Topic 4 Core questions - 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 overall charge on an atom is…

Answer 3

zero/neutral

Question 4

Define element

Answer 4

Contains only one type of atom

Question 5

Substances found in the periodic table are…?

Answer 5

elements

Question 6

Define isotope

Answer 6

An atom of the same element with different numbers of neutrons

Question 7

Define radioactive decay

Answer 7

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

Question 8

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

Answer 8

random

Question 9

Define activity

Answer 9

Rate at which decay occurs

Question 10

What are the units of activity?

Answer 10

Becquerels (Bq)

Question 11

Define count rate

Answer 11

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

Question 12

Defne half life

Answer 12

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 13

Define contamination

Answer 13

The unwanted presence of materials containing radioactive atoms

Question 14

Define irradiation

Answer 14

When an object is exposed to radiation

Question 15

Does an irradiatied object become radioactive itself?

Answer 15

no

Question 16

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

Answer 16

ionisation

Question 17

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

Answer 17

mutations, cancer

Question 18

Define peer review

Answer 18

Checking of scientific results by other scientific experts

Question 19

Define mass number

Answer 19

The total number of protons and neutrons in an atom

Question 20

Define atomic number

Answer 20

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

Question 21

Electrons in atoms are located in ___________

Answer 21

energy levels

Question 22

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

Answer 22

electrons, higher

Question 23

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

Answer 23

electrons, lower

Question 24

Who came up with the Plum Pudding model of the atom

Answer 24

J J Thompson

Question 25

Describe the Plum Pudding model of the atom

Answer 25

A ball of positive charge with negative electrons embedded in it

Question 26

Was the Plum Pudding model correct?

Answer 26

no

Question 27

What experiment did Rutherford do?

Answer 27

Alpha particle scattering

Question 28

What did Rutherford’s experiment reveal?

Answer 28

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

Question 29

Who discovered that electrons are located in energy levels?

Answer 29

Niels Bohr

Question 30

What did Jame Chadwick discover about the atom?

Answer 30

That the nucleus contains neutrons as well as protons

Question 31

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

Answer 31

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

Question 32

Name the three subatomic particles

Answer 32

proton, neutron, electron

Question 33

Which particles are located in the atoms nucleus

Answer 33

protons, neutrons

Question 34

What is the charge of each subatomic particle?

Answer 34

proton +1, neutron 0, electron -1

Question 35

What is the mass of each subatomic particle?

Answer 35

proton 1, neutron 1, elecrton ≈ 0

Question 36

Name the three types of radiation

Answer 36

alpha, beta and gamma

Question 37

What is an alpha particle?

Answer 37

two protons and two neutrons

Question 38

What is a beta particle?

Answer 38

an electron

Question 39

What is gamma radiation?

Answer 39

electromagnetic wave (NOT a particle)

Question 40

What will absorb (stop) alpha radiation?

Answer 40

paper/skin

Question 41

What will absorb (stop) beta radiation?

Answer 41

about 5 mm aluminium

Question 42

What will absorb (stop) gamma radiation?

Answer 42

several centimetres of lead

Question 43

What is the ionising power of alpha radiation?

Answer 43

very high

Question 44

What is the ionising power of beta radiation?

Answer 44

medium

Question 45

What is the ionising power of gamma radiation?

Answer 45

low

Question 46

What is meant by the ionising power of radiation?

Answer 46

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

Question 47

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

Answer 47

decreases by 4

Question 48

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

Answer 48

decreases by 2

Question 49

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

Answer 49

stays the same

Question 50

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

Answer 50

increases by 1

Question 51

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

Answer 51

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