radioactivity and nuclear reactions

Question 1

What is radioactivity?

Answer 1

The breakdown of the unstable nucleus of an atom.

Question 2

What does a radioactive atom decay to produce?

Answer 2

An atom with fewer neutrons/protons (a lighter atom)

Question 3

What is a radioisotope?

Answer 3

The unstable and radioactive isotope of an element

Question 4

What is the half life of an isotope?

Answer 4

The time it takes for one half of the nuclei in a same to undergo radioactive decay.

Question 5

How much of an original sample will remain after one half life?

Answer 5

50%

Question 6

How much of an original sample will remain after 2 half lives?

Answer 6

25%

Question 7

How is polonium mainly used?

Answer 7

As a source of neutrons, generally by combining with beryllium

Question 8

How many known isotopes does polonium have?

Answer 8

Over 25

Question 9

What is polonium’s most common isotope, and what is it’s half life? What does it’s decay produce?

Answer 9

Po-210
138 days
Lead 206 and lots of energy

Question 10

How is radon produced?

Answer 10

The radioactive decay of Radium

Question 11

What is radon’s isotope with the longest half life, and how long is it?

Answer 11

radon-222

4 days

Question 12

radon is a _____ at a normal room temp

Answer 12

colorless radioactive gas

Question 13

What are radium’s properties? (4)

Answer 13

Highly reactive, brilliant white, metal, blackens when exposed to air.

Question 14

What are alpha particles?

Answer 14

Particles that have a nucleus that is the same as helium w/ two protons and two neutrons

Question 15

What happens when an atom undergoes alpha decay?

Answer 15

The atom loses two of its protos and two of it’s neutrons, which form an alpha particle. Atomic # decreases by two, mass # by 4

Question 16

How far does alpha radiation travel? What can it (or cannot it) penetrate?

Answer 16

They travel a very short distance by air

Cannot penetrate skin or a thin sheet of paper.

Question 17

Are alpha particles radioactive? What do they do after losing their energy>

Answer 17

No, they do not decay further.

After losing their energy, they attract to electrons to become helium atoms.

Question 18

What is beta radiation?

Answer 18

Radiation made of high energy electrons (negative charge) sent out by a radioactive/unstable nuclei

Question 19

What happens when an atom undergoes beta radiation?

Answer 19

A neutron becomes a proton. The atomic # increases by 1 and the mass stays the same.

Question 20

How far does beta radiation travel? What can it (or cannot it) penetrate?

Answer 20

Can travel several meters through air but stopped by solid material
Can penetrate human skin but clothing blocks most

Question 21

What is gamma radiation?

Answer 21

Radiation composed of high energy photons (the smallest unit of electromagnetic radiation) that are emitted by radioactive decay of atomic nuclei. Does not cause the identity of an atom to change.

Question 22

How far does gamma radiation travel? What can it (or cannot it) penetrate?

Answer 22

Able to travel many meters in air.
Easily penetrates most materials.
Frequently comes with alpha and beta radiation.

Question 23

What are nuclear reactions?

Answer 23

changes that occur in the structure of the atomic nuclei.

Question 24

What is energy that results from nuclear reactions called?

Answer 24

Nuclear energy or atomic energy

Question 25

What is nuclear fission?

Answer 25

Nuclear reaction where nucleus splits into two smaller parts, normally same size. Releases a lot of energy

Question 26

How is uranium nuclei split?

Answer 26

By bombarding it with neutrons

Question 27

What is nuclear fusion?

Answer 27

Nuclear reaction where the nuclei of two atoms join to make a bigger nucleus. Energy is given off.

Question 28

Nuclear fusion occurs under ery ___ conditions

Answer 28

hot

Question 29

Sun and other stars create energy through ____

Answer 29

nuclear fusion

Question 30

In the sun, hydrogen nuclei ___ to make helium

Answer 30

fuse