Radioactivity

Question 1

what is radiation?

Answer 1

-energy in the form of waves or moving subatomic particles

Question 2

what are the two types of radiation?

Answer 2

• electromagnetic radiation

- nuclear radiation

Question 3

what is electromagnetic radiation?

Answer 3

• consists of energy waves that travel at the speed of light (300,000 km/s) in a vacuum
• includes xrays, microwaves, visible light, uv rays

Question 4

what does the electromagnetic spectrum show?

Answer 4

-different forms of EM radiation

Question 5

what is nuclear radiation?

Answer 5

• atoms that emit radiation from their nucleus are radioactive
• most nuclei dont give off radiation;they are stable bc neutrons hold tgt protons (nuclear force)

Question 6

what types of radiation can radioactive nuclei emit? (3)

Answer 6

• alpha radiation a
• beta radiation B
• gamma radiation Y

Question 7

what is used to detect types of radiation?

Answer 7

-geiger counter

Question 8

what is an alpha particle?

Answer 8

• has 2p and 2n
• charge of 2+
• low penetrating power
• like a helium atom nucleus but is not-no electrons

Question 9

what is a beta particle?

Answer 9

• high speed electrons

- charge of 1-

Question 10

what are gamma rays?

Answer 10

• high energy waves emmitted by nucleus (not particle)

- no charge

Question 11

what is ionizing radiation?

Answer 11

• enough energy to knock electrons off of atoms and produce ions
• can cause damage to human DNA and proteins
• DNA change can lead to cancer
• includes alpha, beta, gamma radiation and xrays

Question 12

what is non-ionizing radiation?

Answer 12

• represented by lower energy waves on EM spectrum
• includes visible light, radiowaves, infrared radiation
• some can cause injury to humans but not as quickly as IR

Question 13

what is ultraviolet radiation? (UV)

Answer 13

• boundary of ionizing and non ionizing radiation

- known to cause DNA skin cell changes

Question 14

what is an isotope?

Answer 14

-different forms of atoms of an element

Question 15

why are isotopes different?

Answer 15

-each form has a different number of neutron in the nucleus but protons are the same

Question 16

what is used to represent isotopes?

Answer 16

-standard atomic notation

Question 17

what does decay mean?

Answer 17

-to fall apart

Question 18

what are stable nuclei of isotopes called?

Answer 18

-unchanging

Question 19

what are unstable nuclei of isotopes called?

Answer 19

-radioactive

Question 20

what type of radiation do radioactive nuclei emit?

Answer 20

-they can emit radiation as alpha particles, beta particles, gamma rays or neutrons

Question 21

what does a nuclear equation show?

Answer 21

• the radioactive decay of an element
• sum of mass number products = mass number of parent
• sum of atomic number products = atomic number of parent

Question 22

what happens in alpha decay?

Answer 22

• alpha particle emitted

- new type of nucleus created

Question 23

in alpha decay what happens to the decay product?

Answer 23

• has atomic number that is two less than parent

- has mass number that is four less than parent

Question 24

what happens in beta decay?

Answer 24

-beta particle emitted

Question 25

in beta decay what happens to the decay product?

Answer 25

• has atomic number that is one greater than the parent

- mass number is same

Question 26

what happens in gamma decay?

Answer 26

-gamma rays emitted

Question 27

in gamma decay what happens to the decay product?

Answer 27

• no particle produced;mass is the same

- indicates parent is unstable and has excess energy;emitted as gamma rays

Question 28

what happens to radioactivity over time?

Answer 28

• there will be fewer nuclei left to decay

- the strength of radioactivity decreases in radioactive material

Question 29

what is half life?

Answer 29

-the time required for half of the nuclei in a radioactive sample to decay

Question 30

what is the original sample of radioactive material called?

Answer 30

-parent isotope

Question 31

what is the resulting stable element after decay called?

Answer 31

-daugter isotope

Question 32

what is a decay curve?

Answer 32

-shows the rate at which a radioisotope decays

Question 33

how do you find the amount of the daughter material?

Answer 33

-starting mass-mass of parent isotope

Question 34

what is nuclear fission?

Answer 34

-the splitting of the nucleus of an atom into parts by bombarding (hitting) it with neutrons

Question 35

what happens when nuclear fission occurs?

Answer 35

-nucleus is split into smaller nuclei and neutrons are released

Question 36

how is a nuclear chain reaction formed?

Answer 36

• neutrons released hit other uranium nuclei–> they slpit

- -> release more energy and neutrons

Question 37

what is the amount of uranium required for a chain reaction called?

Answer 37

-critical mass

Question 38

what happens when a nuclear reaction is not controlled and what does a controlled nuclear reaction do?

Answer 38

• rapid release of energy occurs (like atomic bomb)

- produce energy

Question 39

what is an example of a controlled nuclear reactor?

Answer 39

-CANDU reactor (canadian deuterium uranium)

Question 40

what is nuclear fusion?

Answer 40

-process by which multiple atomic particles join together to form a heavier nucleus and release a great deal of energy

Question 41

where does nuclear fusion naturally occur in and what does it create?

Answer 41

-it occurs in stars and creates the 4th state of matter, plasma

Question 42

what weapon has nuclear fusion been able to make?

Answer 42

-only hydrogen bomb for it is hard to control