UNIT 3 - Nuclear Chemistry

Question 1

what does the stability of an atomic nucleus depend on?

Answer 1

the proton:neutron ratio

Question 2

what is the required neutron:proton ratio for smaller elements?

Answer 2

1:1

Question 3

what is the required neutron:proton ratio for larger (and heavier) elements?

Answer 3

15:1

Question 4

what is radioactivity?

Answer 4

the result of unstable nuclei rearranging to form stable nuclei with emission of energy

Question 5

what is radiation connected with?

Answer 5

radiation is connected solely with the nucleus

Question 6

what is radiation independent of?

Answer 6

physical state of the element and is not affected when the element forms compounds

Question 7

what is alpha radiation (α)?

Answer 7

slow moving positively charged particles attracted to the negative plate

Question 8

what is beta radiation (β)?

Answer 8

fast moving negatively charged particles attracted to the positive plate

Question 9

what is gamma radiation (γ)?

Answer 9

electromagnetic radiation travelling at the speed of light with no deflection

Question 10

what is the nature of alpha radiation?

Answer 10

helium nucleus

Question 11

what is the nature of beta radiation?

Answer 11

electron

Question 12

what is the nature of gamma radiation?

Answer 12

EMR

Question 13

what is the nature of radiation?

Answer 13

what its similar to

Question 14

what is the symbol for alpha radiation?

Answer 14

⁴₂He

Question 15

what is the symbol for beta radiation?

Answer 15

0
-1e

Question 16

what is the symbol for gamma radiation?

Answer 16

doesnt have one

Question 17

what is the charge on alpha radiation?

Answer 17

2+

Question 18

what is the charge on beta radiation?

Answer 18

1-

Question 19

what is the charge on gamma radiation?

Answer 19

doesnt have one

Question 20

what is the mass of an alpha radiation particle?

Answer 20

4 amu

Question 21

what is the mass of a beta radiation particle?

Answer 21

1/2000 amu

Question 22

what is the mass of a gamma radiation particle?

Answer 22

none

Question 23

what happens when a radioactive isotope decays by alpha emission?

Answer 23

the nucleus loses 2 protons and two neutrons

Question 24

what is transmutation?

Answer 24

when the number of protons changes, causing the element to change

Question 25

what happens if a nucleus has too many neutrons?

Answer 25

a neutron will be converted into a proton and an electron

Question 26

how is beta radiation emitted?

Answer 26

the proton stays inside the nucleus and the electron is ejected from the nucleus as beta radiation

Question 27

what does gamma radiation occur with?

Answer 27

other types of radiation

Question 28

what is gamma radiation a mechanism for?

Answer 28

releasing energy

Question 29

what does gamma radiation not affect?

Answer 29

the atomic or mass number

Question 30

what is the disintegration of a nucleus?

Answer 30

an entirely random event and it is impossible to predict when a particular atom will decay

Question 31

in what situations is radioactive decay predictable?

Answer 31

when the atom is unstable

Question 32

what is half-life?

Answer 32

the time taken for half of the nuclei of a particular isotope to decay

Question 33

what is half life abbreviated to?

Answer 33

t 1/2

Question 34

what is the half life of any isotope independant of?

Answer 34

the mass, temperature, pressure, concentration, catalysts, or state of the sample

Question 35

how are radioisotopes used in medicine?

Answer 35

they are used for radioactive labelling in the diagnosis and treatment of disease

Question 36

how are radioisotopes used in industry?

Answer 36

241Am is used in domestic smoke alarms

Question 37

how are radioisotopes used in scientific research?

Answer 37

32P and 14C can be used to determine the uptake of phosphates and carbon dioxide in plants, this technique is called ISOTOPIC LABELLING

Question 38

how is 14C formed?

Answer 38

14C is a radioactive isotope formed in the upper atmosphere by the bombardment of nitrogen by neutrons

Question 39

why is there a constant level of 14C in the atmosphere?

Answer 39

because the rate of formation is equal to the rate of decay

Question 40

what do all living plants and animals contain?

Answer 40

14C

Question 41

what happens when a plant or animal dies?

Answer 41

it no longer absorbs 14C so the level of radioactivity will decrease

Question 42

how can the age of a sample be calculated?

Answer 42

by using half life and comparing the activity with that of current 14C levels