chapter 18: The nucleus: A chemist's view

Question 1

what did Henri Becquerel do

Answer 1

discovered certain minerals were producing penetrating rays called Uranic rays

Question 2

what did marie curie do

Answer 2

1. discover two elements (radium and polonium)

Question 3

what is the nucleus composed of

Answer 3

nucleons (protons + neutrons)

Question 4

what is an isotope

Answer 4

same element but different number of protons

Question 5

what is a radioactive element

Answer 5

unstable element

Question 6

what are a radionuclides

Answer 6

nuclei that are radioactive

Question 7

what are radioisotopes

Answer 7

atoms containing these nuclei

Question 8

what is radioactive decay

Answer 8

radionuclides spontaneously emit particles to form more stable nuclei w/ less energy

Question 9

what is the parent nuclide

Answer 9

the nucleus that is undergoing the radioactive decay

Question 10

what is the daughter nuclide

Answer 10

the new nuclides that are made

Question 11

what is alpha decay

Answer 11

1. loss of an alpha particle
2. most radioactive, but least penetrating
3. atomic number decreases by 2
4. mass # decreases by 4

Question 12

what is beta decay

Answer 12

1. loss of a beta particle
   - beta = high energy electron that moves very fast
   - more penetrating than alpha
   - atomic # increases by one
   - mass # remains the same

Question 13

what is gamma emission and when does it occur?

Answer 13

loss of a gamma particle

1. high energy, least ionizing, most penetrating source
2. no change in the composition of the nucleus
   - occurs after the nucleus undergoes some other decay

Question 14

what is positron emission

Answer 14

1. loss of a positron

2 short lifetime

3. atomic number decreases by 1 ( proton becomes a neutron)
4. mass remains the sane

Question 15

what is a positron

Answer 15

anti electron, same mass but opposite charge

Question 16

what is electron capture

Answer 16

the capture of an electron by the nucleus from the electron cloud

proton becomes a neutron

1. atomic # = increase by 1
2. mass number= stays the same

Question 17

what is nuclear stability

Answer 17

the basis for all important applications related to nuclear processes

Question 18

what is kinetic stability

Answer 18

probability that a nucleus will undergo decomp to form a different nucleus

Question 19

what is thermodynamic stablity

Answer 19

PE of a nucleus compared to the sume of PE of its protons and neutrons

Question 20

what happens to any element with more than one proton

Answer 20

repulsion in the nucleus

Question 21

what holds nucleons together

Answer 21

strong nuclear force

1. found only in the nucleus
2. acts only at close distance
3. exists bc of neutrons

Question 22

what happens to the stablity as the nuclei gets bigger

Answer 22

it takes more neutrons to stablize the nucleus