Radioactivity Flashcards
what is radiation?
-energy in the form of waves or moving subatomic particles
what are the two types of radiation?
- electromagnetic radiation
- nuclear radiation
what is electromagnetic radiation?
- 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
what does the electromagnetic spectrum show?
-different forms of EM radiation
what is nuclear radiation?
- 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)
what types of radiation can radioactive nuclei emit? (3)
- alpha radiation a
- beta radiation B
- gamma radiation Y
what is used to detect types of radiation?
-geiger counter
what is an alpha particle?
- has 2p and 2n
- charge of 2+
- low penetrating power
- like a helium atom nucleus but is not-no electrons
what is a beta particle?
- high speed electrons
- charge of 1-
what are gamma rays?
- high energy waves emmitted by nucleus (not particle)
- no charge
what is ionizing radiation?
- 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
what is non-ionizing radiation?
- 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
what is ultraviolet radiation? (UV)
- boundary of ionizing and non ionizing radiation
- known to cause DNA skin cell changes
what is an isotope?
-different forms of atoms of an element
why are isotopes different?
-each form has a different number of neutron in the nucleus but protons are the same
what is used to represent isotopes?
-standard atomic notation
what does decay mean?
-to fall apart
what are stable nuclei of isotopes called?
-unchanging
what are unstable nuclei of isotopes called?
-radioactive
what type of radiation do radioactive nuclei emit?
-they can emit radiation as alpha particles, beta particles, gamma rays or neutrons
what does a nuclear equation show?
- the radioactive decay of an element
- sum of mass number products = mass number of parent
- sum of atomic number products = atomic number of parent
what happens in alpha decay?
- alpha particle emitted
- new type of nucleus created
in alpha decay what happens to the decay product?
- has atomic number that is two less than parent
- has mass number that is four less than parent
what happens in beta decay?
-beta particle emitted
in beta decay what happens to the decay product?
- has atomic number that is one greater than the parent
- mass number is same
what happens in gamma decay?
-gamma rays emitted
in gamma decay what happens to the decay product?
- no particle produced;mass is the same
- indicates parent is unstable and has excess energy;emitted as gamma rays
what happens to radioactivity over time?
- there will be fewer nuclei left to decay
- the strength of radioactivity decreases in radioactive material
what is half life?
-the time required for half of the nuclei in a radioactive sample to decay
what is the original sample of radioactive material called?
-parent isotope
what is the resulting stable element after decay called?
-daugter isotope
what is a decay curve?
-shows the rate at which a radioisotope decays
how do you find the amount of the daughter material?
-starting mass-mass of parent isotope
what is nuclear fission?
-the splitting of the nucleus of an atom into parts by bombarding (hitting) it with neutrons
what happens when nuclear fission occurs?
-nucleus is split into smaller nuclei and neutrons are released
how is a nuclear chain reaction formed?
- neutrons released hit other uranium nuclei–> they slpit
- -> release more energy and neutrons
what is the amount of uranium required for a chain reaction called?
-critical mass
what happens when a nuclear reaction is not controlled and what does a controlled nuclear reaction do?
- rapid release of energy occurs (like atomic bomb)
- produce energy
what is an example of a controlled nuclear reactor?
-CANDU reactor (canadian deuterium uranium)
what is nuclear fusion?
-process by which multiple atomic particles join together to form a heavier nucleus and release a great deal of energy
where does nuclear fusion naturally occur in and what does it create?
-it occurs in stars and creates the 4th state of matter, plasma
what weapon has nuclear fusion been able to make?
-only hydrogen bomb for it is hard to control
