Nuclear Chemistry

Question 1

French scientist who discovered radiation using Uranium salt in 1896

Answer 1

Henri Becquerel

Question 2

When fluorescent U salt is exposed to light it will give off

Answer 2

x-rays

Question 3

In the absence of light U, salt gave off an “invisible something” called

Answer 3

radiation

Question 4

1898 - discovered new radioactive elements (Polonium) while student the mineral pitchblende

Answer 4

Marie Curie and Pierre Curie

Question 5

Curies discovered another radioactive element after Polonium called ______, which means shining element.

Answer 5

Radium

Question 6

Po and Ra are both more _______ than Uranium

Answer 6

radioactive

Question 7

________ is the release of energy and matter that results from changes in the nucleus of an atom.

Answer 7

radioactivity

Question 8

_____________ is the energy associated with the strong force that holds the protons and neutrons together.

Answer 8

binding energy

Question 9

radioactivity

Answer 9

The release of energy and matter that results from changes in the nucleus of an atom.

Question 10

Binding Energy

Answer 10

The energy associated with the strong force that holds the protons and neutrons together.

Question 11

Z (nuclear notation)

Answer 11

number of protons, atomic number

Question 12

N (nuclear notation)

Answer 12

number of neutrons

Question 13

A (nuclear notation)

Answer 13

mass number

Question 14

Calculated mass is always ___ than the actual mass of an atom

Answer 14

greater

Question 15

_______ is the mass equivalent of the energy associated with the strong force to keep the nucleus together.

Answer 15

Mass defect

Question 16

Nuclear binding energy is calculated using

Answer 16

Einstein’s famous equation, E = mc^2

Question 17

The higher the BE/nucleon the more stable the ________ is

Answer 17

nucleus

Question 18

The higher the ___________ the more stable the nucleus is

Answer 18

BE/nucleon

Question 19

Steps to calculate BE/nucleon

Answer 19

1. Number of protons, neutrons, electrons.
2. Calculate total mass of all particles.
3. Subtract actual mass ( this gives mass defect)
4. Convert mass defect to Kg
5. Convert mass defect to energy
   (E = mc^2 to get binding energy)
6. Divide by mass number (This gives BE/nucleon)

Question 20

Atoms with unstable nuclei are _______

Answer 20

radioactive

Question 21

Unstable nuclei are caused by an imbalance in the number of

Answer 21

protons and neutrons.

Question 22

Elements with atomic numbers greater than 83 are

Answer 22

radioactive

Question 23

Many elements with atomic numbers smaller than 84 have at least one

Answer 23

radioactive isotope

Question 24

The most important reason that some nuclei are stable and others are not is

Answer 24

the competition between the attractive nuclear force and the repulsive electrical force

Question 25

An unstable nucleus loses energy by emitting radiation during a process called

Answer 25

radioactive decay

Question 26

What are the three basic types of radiation?

Answer 26

alpha particles beta particles gamma rays

Question 27

Positively charged helium nucleus with a mass of 4 and atomic # of 2 no penetrating power (barely go through paper) low speed When an atom loses an alpha particle the atomic number of the product atom is lower by 2 and its mass # is lower by 4

Answer 27

Alpha particles

Question 28

Negatively Charged An electron 100 times more penetrating than alpha particles travel at speeds close to the speed of light beta delay occurs when fast moving electrons formed by decomposition of a neutron in the nucleus of an atom are shot out of the nucleus

Answer 28

Beta Particles

Question 29

No charge high energy electromagnetic radiation often produced along with alpha or beta particles does not alter the atomic number or mass number of an atom most penetrating of all radiation types (penetrates up to 7 cm of lead)

Answer 29

gamma rays

Question 30

each atom of an element in a nuclear reaction is represented by

Answer 30

the chemical symbol

Question 31

what two small numbers are written in nuclear reactions?

Answer 31

upper left = mass # | lower left = atomic #

Question 32

a particle with the mass of an electron but a positive charge. It may be emitted as a proton is converted to a neutron.

Answer 32

positron

Question 33

An electron is captured by a proton which produces a neutron. The atom has loses one in its atomic number but loses no mass

Answer 33

Electron Capture

Question 34

Characteristic rate of decay of every radioisotope (radioactive isotope)

Answer 34

Half-Life

Question 35

The time required for half of the atoms of a radioisotope to emit radiation and to decay to products

Answer 35

half-life

Question 36

After one half life, half of the original radioactive atoms have decayed into atoms of a new element. What happens to the other half?

Answer 36

It remains unchanged

Question 37

After a second half life, how much of the original radioactive atoms remain?

Answer 37

one quarter

Question 38

How long are half-lives?

Answer 38

They may be as short as a fraction of a second or as long as several million years.

Question 39

Change of one element into another as a result of nuclear changes (naturally or through artificial means)

Answer 39

Transmutation

Question 40

Spontaneous breakdown will continue until a stable nonradioactive nucleus is formed.

Answer 40

Radioactive decay

Question 41

Who performed the first artificial transmutation?

Answer 41

Ernest Rutherford

Question 42

Rutherford's experiment led to the discovery of what?

Answer 42

The proton

Question 43

Who discovered the neutron during a transmutation experiment?

Answer 43

James Chadwick (1932)

Question 44

Z>92 None of these occur in nature All are radioactive have been synthesized in nuclear reactors and nuclear accelerators which accelerate the bombarding particles to very high speeds.

Answer 44

Transuranium Elements

Question 45

These transuranium elements are the first artificial elements ever made (1940)

Answer 45

Pu and Np

Question 46

Splitting of a nucleus into smaller nuclei of approximate equal mass Does not occur spontaneously The nuclei of an element is bombarded with neutrons

Answer 46

Nuclear Fission

Question 47

Fission continues by _____ ________. Some of the neutrons produced react with other fissionable atoms producing more n^0 than react with still more fissionable atoms.

Answer 47

chain reaction

Question 48

_______ produces great amount of energy.

Answer 48

Fission

Question 49

Whats an example of an uncontrolled chain reaction?

Answer 49

An atomic bomb

Question 50

Controlled fission produces what? (done in nuclear reactors)

Answer 50

useful energy

Question 51

neutron moderation (does this to neutrons)

Answer 51

slows down neutrons

Question 52

neutron absorption (does what to the number of slow n^0)?

Answer 52

decreases

Question 53

Occurs when 2 nuclei combine to produce a nucleus of heavier mass.

Answer 53

Nuclear Fusion

Question 54

Energy released from the sun is the result of what?

Answer 54

nuclear fusion

Question 55

Releases more energy than fission Only takes place at very high temperature Appealing as energy source

Answer 55

Solar fusion