Chapter 21 - Nuclear Chemistry

Question 1

Chemical energy is associated with _______.

Answer 1

the making and breaking of chemical bonds

Question 2

Nuclear energy is _______ in comparison to chemical energy.

Answer 2

enormous

Question 3

______ % of worldwide energy use comes from nuclear energy.

Answer 3

13%

Question 4

Nuclear energy is due to changes in the nucleus of atoms _________.

Answer 4

changing them into different atoms

Question 5

The nucleus is composed of the two ______, protons and neutrons.

Answer 5

nucleons

Question 6

The number of ____ is the atomic number.

Answer 6

protons

Question 7

The number of ________ is the mass number.

Answer 7

protons and neutrons together

Question 8

Define isotope.

Answer 8

each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties

Question 9

It is not uncommon for some nuclidies of an element to be unstable, or ______.

Answer 9

radioactive

Question 10

Define radionuclide.

Answer 10

an unstable nuclide of an element

Question 11

List five types of radioactive decay.

Answer 11

Alpha decay
Beta decay
Gamma emission
Positron emission
Electron capture

Question 12

Define alpha decay.

Answer 12

the loss of an α-particle

Question 13

Define beta decay.

Answer 13

the loss of a β-particle (a high-speed electron emitted by the nucleus)

Question 14

Define gamma emission.

Answer 14

Gamma emission is the loss of a γ-ray, which is high-energy radiation that almost always accompanies the loss of a nuclear particle

Question 15

Define positron.

Answer 15

a particle that has the same mass as, but an opposite charge to, that of an electron

Question 16

Some nuclei decay by emitting a _____, a particle that has the same mass as, but an opposite charge to, that of an electron.

Answer 16

positron

Question 17

An electron from the surrounding electron cloud is absorbed into the nucleus during _____.

Answer 17

electron capture

Question 18

_________ helps keep the nucleus together.

Answer 18

strong nuclear force

Question 19

Any atom with more than one proton (anything but H) will have _____ between the protons in the nucleus.

Answer 19

repulsion

Question 20

Neutrons play a key role _____ the nucleus, so the ratio of neutrons to protons is an important factor.

Answer 20

stabilizing

Question 21

For smaller nuclei (Z ≤ 20), _____ nuclei have a neutron-to-proton ratio
close to 1:1.

Answer 21

stable

Question 22

As nuclei get _____, it takes a larger number of neutrons to stabilize the nucleus.

Answer 22

larger

Question 23

Nuclei above the _____ have too many neutrons, so they tend to decay by emitting beta particles

Answer 23

belt of stability

Question 24

Nuclei below the belt of stability have too many ____, so they tend to become more stable by positron emission or electron capture.

Answer 24

protons

Question 25

There are _____ stable nuclei with an atomic number greater than 83.
Nuclei with such large atomic numbers tend to decay by _____.

Answer 25

no, alpha emission

Question 26

List the magic proton numbers.

Answer 26

2, 8, 20, 28, 50, 82

Question 27

List the magic neutron numbers.

Answer 27

2, 8, 20, 28, 50, 82, 126

Question 28

Nuclei with an _____ number of protons and neutrons tend to be more stable than those with odd numbers

Answer 28

even

Question 29

_____ can be induced by accelerating a particle to collide it with the nuclide.

Answer 29

nuclear transmutations

Question 30

_____ (“atom smashers”) are enormous, having circular tracks with radii that are miles long.

Answer 30

particle accelerators

Question 31

Radioactive decay is a _______ process.

Answer 31

first order

Question 32

Half-life is the time required for _____ of a radionuclide sample to decay.

Answer 32

half

Question 33

_____ is the rate at which a sample decays.

Answer 33

activity

Question 34

Define Becquerel (Bq).

Answer 34

one desintegration per second