Chapter 2; Atomic Structure and Radioisotopes Flashcards
elements consist of only […] type of atom, and cannot be broken down into anything […]
One
Smaller
compounds ..
consists of more than one type of atom, and can be broken down into their elements by chemical means
atoms..
consist of a small, very dense nucleus containing protons and neutrons, surrounded by electrons that are rapidly moving
electron cloud is..
the region where electrons are more likely to be found
mass of atoms expressed as relative units
atomic mass units (amu) or daltons (Da)
protons (+1) and neutrons (zero charge) are located in the …
nucleus
electrons (-1) are located in the
electron cloud
subatomic particle
Charge and mass
proton
neutron
electron
+1 1.007
0 1.009
-1 0.000559
mass of an atom is compromised of…
protons and neutrons
volume of an atom
determined by electrons
charge of an atom
determined by number of protons and electrons
atomic symbol…
abbreviation assigned to each element
atomic number…
number of protons
atomic mass
average mass of the atoms of an element
what are group elements
going down on periodic table
what are periods
going across periodic table
what can too much fluoride cause
bones and teeth brittle
+
enlarged thyroid
atomic number =
protons and electrons
how to find neutrons
mass - atomic # (protons)
all atoms of an element
- contain the same number of protons and electrons
- may contain different numbers of neutrons
isotopes …
are atoms with the same number of protons but different number of neutrons
(different forms of a single element)
how to identify mass number with isotopes (diff neutrons)
mass # = # protons +# neutrons
how to name an isotope with its name
element name-mass number
e.g. iodine-125
how to name an isotope with its symbol
atomic symbol-mass number
I-125
how to name an isotope as a nuclear symbol
mass number
atomic number (right of both in middle atomic symbol)
e.g.
125
I
53
how to calculate average atomic mass
(mass isotope 1) x (fractional abundance) + ( mass isotope 2) x (fractional abundance)
side note; fractional abundance is divided by 100%
what group is group 1A
alkali metals
what group is group 2A in
alkali earth metals
what group is group 7A in
halogens
what group is group 8A in
noble gases
what group is the middle in
transition metals
what group is the bottom, left over, elements in
inner transition elements
what groups are main group elements
1A - 8A
elements within a group share…
similar physical and chemical properties
what do the arrangement of electrons represent
physical and chemical properties of the elements
what is quantum mechanics
electrons can have only certain allowed energy levels
n= symbol for allowed energy levels
electrons are always moving so they have…
kinetic energy
valence electrons
interacting with matter , outermost electrons, form compounds
farthest from nucleus
how to determine the number of valence electrons
of group (e.g. 1A = 1 va, 8A = 8 va)
radioisotopes …
(radioactive isotope)
- unstable nucleus
- undergoes decay to become more stable (spontaneous process)
- radiation is emitted during decay
what are the high energy particles of radiation
a (alpha ) particle
B (beta) particle
what are the high energy light wave
y (gamma)-ray
x-ray
all isolates with atomic number greater than […] are radioactive
82
what does the alpha decay release
alpha particle from isotope
- slow moving, high energy particle, +2 charge
4
a
2
what is nuclear equation
parent nuclide -> daughter nuclide + a particle
B (beta) decay
release of a beta particle
- travel 90% speed of light
- high energy electron
daughter nuclide has
- same mass number as the parent
- atomic # = to the parent atomic number +1
0
B
-1
half life …
time needed for 1/2 of the parent nuclides to decay into daughter nuclides
- different radioisotopes decay at different rate
- radioisotopes decay exponentially
alternate half life approach
N = (1/2) ^n
N fraction of isotope remaining
n number of half lives
electromagnetic radiation (light)…
- energy that travels through space as a wave
- different light waves have different wavelengths
wavelength - distance from top of one wave crest to next
- radio waves - very long wavelengths ( low energy)
- gamma rays - very short wavelengths (high energy= more potential damage to us)
energy of light waves is inversely proportional to wavelenght
long wavelengths = lower energy
short wavelengths = higher energy
- ionizing radiation can dislodge valence radiation
(gamma rays, X-rays, higher energy UV)
daughter nuclide initially may be produced in an […] (high energy), also called […}
excited state
metastable (m)
0
Y (gets rid of m)
0
release of gamma rays for more stable state
parent nuclide =
unstable
daughter nuclide can also be unstable so…
release gamma rays
exposure can be
acute (single exposure) or
chronic (many smaller doses)
radiation sickness…
results from acute exposure to radiation
absorbed dose radiation - gray (Gy) …
measures amount of energy absorbed by an individual
effective dose - sievert (Sy) …
represents the biological damage based on both the energy and the penetrating power of the radiation
