P6.1

Question 1

what is an atomic nuclei composed of?

Answer 1

protons and neutrons

Question 2

what is the charge on atomic nuclei?

Answer 2

positive

Question 3

how would having atoms of the same element differ in nuclear mass?

Answer 3

by having a different number of neutrons

Question 4

why would nuclei emit alpha/ beta particles, neutrons and/or gamma rays?

Answer 4

because some nuclei are unstable

Question 5

describe alpha radiation

a) the structure
b) the symbol
c) how it is produced
d) the equation symbol
e) the charge

Answer 5

a) particle
b) α
c) 2 protons and 2 neutrons emitted from the nucleus
d) 4
He
2
e) +2 charge

Question 6

in simple terms what is radioactivity?

Answer 6

energy emitted by a nucleus

Question 7

describe beta radiation

a) the structure
b) the symbol
c) how it is produced
d) the equation symbol
e) the charge

Answer 7

a) particle
b) β
c) neutron turns into a prelectron emitted by nucleus
d) 0
e
-1
e) -1 charge (ITS AN ELECTRON)

Question 8

do electrons orbit around the nucleus?

and if not, what do they do instead

Answer 8

• they do not

- they occupy discrete energy levels

Question 9

where is the lowest energy level on an atom?

and what is it called

Answer 9

closest to the nucleus

- called ground state

Question 10

do all atoms have the same values for energy levels?

Answer 10

no, different atoms have different values for energy levels

Question 11

how can an electron be excited?

Answer 11

by absorbing EM radiation

Question 12

what causes electrons to move up to a higher energy level (from a low energy level)

Answer 12

by gaining energy (ie. absorbing EM radiation)

Question 13

what does it mean when an electron is excited?

Answer 13

inner electron rises to a higher energy level

Question 14

what does it mean when an atom has been ionised?

Answer 14

the outer electron has absorbed enough EM radiation to leave the atom entirely

• so atom becomes a positively charged ion

Question 15

what us the best way to excite electrons?

Answer 15

shine light on them

Question 16

when can an electron absorb a photon?

and what happens when it does so

Answer 16

when the energy of the photon matches exactly the energy difference between two levels

• it excites to a higher energy level

Question 17

if a photon’s energy is slightly above the energy difference between tht two levels, will it be absorbed by the electron?

Answer 17

no it will not, it must be the EXACT difference

Question 18

what happens to the photon when it is absorbed?

Answer 18

disappears

Question 19

what happens if a photon is not absorbed?

Answer 19

it passes straight through the atom

Question 20

can a photon be partially absorbed by an electron?

Answer 20

no, must be absorbed ENTIRELY by a single electron

Question 21

what is the energy of the photon proportional to?

Answer 21

proportional to the frequency of the EM radiation (and so a specific wavelength)

Question 22

why do electrons return to their original energy levels?

Answer 22

as only a certain number of electrons are allowed to exist at any given energy level

Question 23

explain what happens when electrons de-excite

Answer 23

• emit energy as radiation (in the form of photons)

Question 24

can atoms/nuclei only generate and absorb specific frequencies?

Answer 24

no, radiation can be absorbed/emitted from any part of the EM spectrum

• as it depends on how much energy is needed for an electron to move to a higher energy level

Question 25

when electrons de-excite, do they emit the energy all at once?

Answer 25

can be all at once, or a series of steps

• but total radiation emitted is equal to the radiation/energy absorbed by photon

Question 26

what does an absorption spectrum show?

Answer 26

a set of frequencies of radiation absorbed by an atom when excited electrons move to higher energy levels

Question 27

how can you use an absorption spectrum to see what an atmosphere is made of?

Answer 27

as the black lines show which frequencies are missing/have been absorbed

• and each atom absorbed certain frequencies/wavelengths in the EM spectrum

Question 28

what does an emission spectrum show?

Answer 28

set of frequencies of radiation emitted by an atom when excited electrons move to lower energy levels

Question 29

are the energies that electrons have in an atom positive or negative?

Answer 29

always negative, as they are ‘bound’ to the atom

Question 30

what is a photon?

Answer 30

a packet of energy in which EM radiation is emitted and absorbed

Question 31

why would an object emit visible light after absorbing UV radiation?
(ie. glow in the dark objects)

Answer 31

• as the radiation emitted by the de-exciting electrons is released in a series of steps
• which have photons of a lower energy released (and therefore frequency)
• so a different wavelength is emitted
• wheras visible light was absorbed in one go