Chapter 19 Radioactivity and Nuclear chemistry
how many isotopes of carbon exist in nature?
3,
all nuclides with __ or more protons are radioactive
84
occurs when an unstable nucleus emits a particle composed of two P and two N
Alpha Decay
charge of ⁺2 and mass of 4 amu, helium nucleus
Alpha Rays
who designed the experiment to determine the phosphorescent minerals also gave off x-rays
Antoine-Henri Becquerel
who discovered radioactivity
Antoine-Henri Becquerel
__________ chemistry keeps producing C-14 at nearly the same rate it decays
Atmospheric
10x more penetrating than alpha but only 1/2 ionizing
Beta
occurs when an unstable nucleus emits an electron
Beta Decay
charge of -1 and negligible mass, electron-like
Beta Rays
which carbon isotope is radioactive
C-14, half-life=5730yrs
Form of light energy, not a particle
Gamma Rays
who determined the rays were emitted from specific elements
Marie Curie
stability of the nucleus can be shown with the ratio between
N:P
in miner dating, compare the amount of U-238 with....?
Pb-206 in volcanic rocks and meteorites
charge +1 and negligible mass
Postiron
proton changing into a neutron
Postiron
similar to beta particles in their ionizing and penetrating ability
Postiron Emission
_______ can expose light-protected photographic film
Radioactive Rays
the release of tiny, high-energy particles/gamma rays from an atom
Radioactivity
What did marie curie rename it? and why?
Radioactivity, rays were no longer just a property of uranium
Marie Curie also discovered new elements:
Radium and Polonium
who discovered the types of rays
Rutherford
each radionuclide had a particular length of time required to lose half its radioactivity
a constant half-life
how to neutrons stabilize the nucleus
add to the strong force but don't repel each other like protons do
by measuring and comparing the amt. of a parent RA Isotope and stable daughter, we can determine
age of the object
radioactive rays cause
air to become ionized
Becquerel determined...
all the minerals that produced these rays contained uranium, and the rays were produced even though the mineral was not exposed to outside energy.
most ionizing but least penetrative
alpha
what are the three types of rays
alpha, beta, gamma
mass # same, atomic # decreases by 1
atom loses a positron from the nucleus
Z
atomic number
all things that are alive/were alive contain _____________
carbon
what do chemical reactions involve
changes in electronic structure of the atom
radioactivity is not a _____________________
chemical reaction
radioactive rays cause certain _________ to give off a flash of light when they strike the _______
chemicals/chemical
new nucleus that is made
daughter nuclide
what can nuclear radiation treat?
diseases because the radiation is ionizing, allowing it take unhealthy tissue
No particle emission, but atom changes
electron capture
occurs when an inner orbital e- is pulled into the nucleus
electron capture
detects radiation by its ability to penetrate the flask and ionize the air inside
electroscope
Particles emitted by radioactive nuclei have a lot of ______ and therefore can be ________
energy, readily detected
most stable nuclei
even number of P and N
we may use photographic film to detect the presence of radioactive rays
film badge dosimeters
processes with a constant half-life follow what order?
first order kinetic rate laws
Polonium: named for
for her homeland
least ionizing, most penetrating
gamma emission
occurs after the nucleus undergoes some other type of decay and remaining particles rearrange
gamma emission
works by counting e- generated when Ar gas atoms are ionized by radioactive rays
geiger-muller counter
Radium: named for
green phosphorence
Radioactive ray can/have
ionize matter, high energy, penetrate matter, cause phosphorescent chemicals to glow
atomic number increases by 1, mass stays the same
loss of a beta particle
atomic # decreases by 2, mass number decreases by 4
loss of an alpha particle
A
mass number
if the total number of nucleons adds to a magic number the nucleus is
more stable
the _____ play an important role in stabilizing the nucleus
neutrons
if N/Z ratio is too high
neutrons are converted to protons via B decay
changes in the structure of the nucleus
nuclear reactions
where are particles ejected from
nucleus
the nucleus of an isotope
nuclide
nucleus that is undergoing radiative decay
parent nuclide
the long-lived emission of light by atoms or molecules that sometimes occurs after they absorb light
phosphorescence
the change in the amt. of radioactivity of a particular radionuclide is ________ and not affected by _________________
predictable, environmental factors
mass # same, atomic number decreases by 1
proton combines with e- to make N
if N/Z ratio is too low
protons are converted to neutrons via position emission/ electron capture
when radioactive nuclei spontaneously decompose into a smaller nuclei
radioactive decay
most nuclides are
radionuclides
is constant and different for each radioactive isotope
rate of change in the amt. of radioactivity
who discovered transmutation
rutherford
able to count the number of flashes/minute
scintillation counter
strong force acts only over ______ distance
short
what undergoes electron capture
some unstable nuclei
the particles in the nucleus are held together by a very strong attractive force only found in the nucleus
strong force
rate of radioactive change was not affected by?
temperature
the shorter the half-life
the more nuclei decay every second
for one element to change into another
the number of P in the nucleus must change
How can nuclear radiation be used?
to visualize/ test structures in the body and see if they are operating properly
during the radioactive process, atoms of one element are changed into atoms of a different element
transmutation
radioactive nuclei are
unstable
what did becquerel call these
uranic rays, made of uranium
______ are detected by their ability to penetrate matter and expose a photographic plate.
x-rays
