Nuclear Chemistry

for Kolb's class :3

define radioactivity

the spontaneous emission of radiation

define radiation

the emission of electromagnetic waves or subatomic particles (what is emitted during radioactive decay)define

define radioisotope

the nuclei of unstable isotopes

alpha particle

beta particle

gamma ray

What does the stability of a nucleus depend on?

the nucleus has to be balanced (right amount of protons and neutrons)

How does an unstable nucleus release energy?

it emits radiation; radioactive decay occurs

penetrating power of an alpha particle

low; can be stopped by a sheet of paper

penetrating power of a beta particle

medium; can be stopped by a block of wood

penetrating power of a gamma ray

high; can be stopped by several meters of concrete

What part of the atom undergoes change during radioactive decay?

the nucleus undergoes change

define band of stability

the region that the stable nuclei are in 

define positron

a particle with the mass of an electron but the charge of a proton

define half-life

time required for ½ of the nucleus of an isotope to decay

define transmutation

the process by which an element changes into another element 

define transuranium elements

they are the elements on the periodic table above # 92 (uranium); all of them undergo transmutation

define electron capture

when an electron is absorbed into the nucleus 

What is distinct about elements with an atomic number below 20? 

the ratio of protons to neutrons is approximately 1 to 1

Above atomic number 20, stable nuclei must have more…

more neutrons than protons

What type of decay occurs if the nucleus contains too many neutrons?

Neutron decay

What is another name for “electron capture”?

inverse beta emission

Nuclei with atomic #s greater than what are radioactive?

greater than 92

How are half-lives used to calculate the age of a formerly living organism?

archaeologists can measure the amount of C-14 that an object contains (measuring the ratio of C-14 to other C isotopes w/half-lives)

half-life formula

define nuclear fission

the splitting of a nucleus into smaller fragments

define nuclear fusion

when nuclei combine to form a nucleus of greater mass

medical uses of nuclear radiation

diagnostics, cancer treatment, food safety

How does a nuclear power plant work?

energy from nuclear fission leads to electricity being generated