Nuclear Chemistry

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alpha particle
a helium nucleus that is emitted from a radioactive atom. Alpha particles are a form of radiation called (you guessed it) alpha radiation.

aka- 4(top) 2(bottom) alpha symbol or 4(top) 2(bottom)He

beta particle
a high speed electron that is emitted from a radioactive atom. Beta particles are a form of radiation called beta radiation.
gamma particle
a high-energy photon (particle of light) that is emitted from a radioactive nucleus. Gamma particles have zero mass and so do not affect the math in the word problems in this unit.

Since light can have either wavelike or particle-like properties, you will often see this written as “gamma ray” rather than “gamma particle.”

symbol for alpha particle
symbol for alpha particle
symbol for beta particle
symbol for beta particle
symbol for gamma particle or gamma ray
symbol for gamma particle or gamma ray
Arrange alpha, beta, and gamma particles in order of increasing ability to penetrate matter.
Arrange alpha, beta, and gamma particles in order of increasing ability to penetrate matter.
alpha < beta< gamma. (Alpha can't go through paper. Beta can go through paper but not plywood. Gamma can go through moderately-thick layers of lead, but is stopped by thick layers of lead.)
nuclear radiation
the emission of alpha particles, beta particles, or gamma rays from the nucleus of an atom
mass number
the number of protons and neutrons in the nucleus of an atom

When written in standard form, this is the top number.

atomic number
the number of protons in the nucleus of an atom. The number of protons is unique to each element and defines that element. When written in standard form, this is the bottom number.

Example: there is one and only one element in the whole universe with 6 protons, and that atom is carbon.

isotope
Atoms that have the same number of protons (and are therefore the same element) but different numbers of neutrons.

Isotopes are chemically identical, but some may be radioactive while others are not.

Carbon-12 and Carbon-13 are isotopes. Carbon-13 is a radioisotope (decays), while Carbon-12 is quite stable.

radioisotope
radioisotope
an isotope that emits alpha particles, beta particles, and/or gamma rays.
atomic mass
atomic mass
All elements have several isotopes that exist in nature. Atomic mass is the weighted average of all the isotopes of an element.
Using the periodic table and your knowledge of nuclear chemistry terminology, give the symbol for carbon-14.
Based on your knowledge and on the symbol for carbon-14, how many protons does carbon-14 have? How many neutrons?
Carbon-14 has 6 protons (the number on the bottom, aka the atomic number) as does every isotope of carbon. (6 protons is what makes it carbon) The number on the top, the mass number, is protons + neutrons, so 14 – 6 = 8 neutrons.
Using the periodic table and your knowledge of nuclear chemistry terminology, give the symbol for lead-212
Using the periodic table and your knowledge of nuclear chemistry terminology, give the symbol for lead-212
Using the periodic table and your knowledge of nuclear chemistry symbols, show where the mass number is in the symbol for uranium-235. (Sometimes abbreviated as U-235)
(Remember that the mass number is the total number of protons and neutrons)
Using the periodic table and your knowledge of nuclear chemistry symbols, show where the atomic number is in the symbol for uranium-235.
Using the periodic table and your knowledge of nuclear chemistry symbols, show where the atomic number is in the symbol for uranium-235.
(Remember that the atomic number is the total number of protons and defines the element. Because the symbol tells what the element is anyway, the mass number is sometimes omitted unless needed for calculations.)
Write out the equation that represents carbon-14 undergoing beta decay.
Write out the equation that represents carbon-14 undergoing beta decay.
Note that the superscripts and subscripts on the right total up to those on the left. The mass number doesn’t change since beta decay is caused by a neutron breaking down into a proton.
Write out the equation that represents sulfur-35 undergoing beta decay.
Write out the equation that represents sulfur-35 undergoing beta decay.
Again, note the superscripts and subscripts on each side of the equation total up to the same numbers.
Write out the equation that represents uranium-238 undergoing alpha decay.
Write out the equation that represents uranium-238 undergoing alpha decay.
Write out the equation that represents radium-222 undergoing alpha decay.
Radioactive half-life
The radioactive half-life for a given radioisotope is the time for half the radioactive nuclei in any sample to undergo radioactive decay.
For example, if a radioisotope has a half-life of 5 years, then 50% of it will be gone in 5 years, 50% of the remaining isotope will be gone 5 years after that (leaving a total of 25%), 12.5% will be left 5 years after that, 6.25% 5 years after that, etc.
Categories: Nuclear Chemistry