Nuclear Chemistry and Fundamentals of Atoms (AP Chem)

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Atomic Theory
A theory that states:
1. Atoms are the fundamental unit of matter
2. Atoms are very small
3. Atoms are very numerous
4. There are about 110 types of atoms called elements (see Periodic Table)
5. All atoms of the same element are identical in number of protons and chemical properties
6. All atoms of one element behave differently than atoms of other elements
Atomic structure
A densely-packed positively-charge area called the nucleus surrounded by an “electron cloud” that is mainly empty space with a positive charge
A weighted sub-atomic particle that carries a positive charge and is used to identify elements
A weighted sub-atomic particle that has no charge and has variance across atoms of an element
A practically weightless sub-atomic particle that has a negative charge
A small, dense area in an atom where the protons and neutrons are packed together; carries a positive charge and the majority of the weight in an atom
Electron Cloud
A general area where electrons can be found in an atom, but is mostly empty space; carries a negative charge and has practically no weight
Weak force
Forces involved with radioactivity (ie. spontaneous “self-destruction” of unstable nuclei)
Strong force
A very strong force that over comes the repulsion of protons to hold the nucleus together, but only works over very short distances
Gravitational force
Attractive forces between any objects with mass that increases proportionately with mass and proximity but does not have major affects at the atomic level
Electromagnetic force
Either attractive or repulsive forces between objects of similar or different charges respectively that is very strong and crucial for atomic and molecular structure which increase proportionately with charge and proximity
Atomic number
The number of protons that all atoms of a particular element have in the nucleus
Atomic symbol
The one or two letter representation given to an element on the Periodic Table
Neutral atom
An atom with no overall charge that has the same number of protons and electrons
An atom that has an overall charge that has lost or gain electrons from the outer edges of the electron cloud
An atom with an overall negative charge from gaining (an) electron(s)
An atom with an overall positive charge from losing (an) electron(s)
Mass number
The number of protons and neutrons that equal approximately the total mass of a particular atom
Nuclide symbol
A short-hand way to show the number of protons, electrons, and neutrons in a partuclar atom; constructed using the element symbol with its mass number in superscript and its atomic number in subscript to the left and the charge in superscript to the right
An atom of an element with a different number of neutrons in the nucleus which has a different weight
Percent abundance
The natural ratio of isotopes
Atomic weight
The average atomic molar weight of all isotopes of an element in proportion to their natural abundance; almost never whole numbers that are closest to the weight of their largest percent abundance
Atomic weight equation
AW = (fractional abundance 1)(mass of isotope 1) + (fractional abundance 2)(mass of isotope 2) + …
Mass spectrometer
A machine that is used to find that exact mass of atoms or molecules
Chemical reactions
Reactions that involve valence electrons that does not change the identity of the elements involved
Nuclear reactions
Reactions during which nuclei change due to inherent instability or bombardment
Sub-atomic particles, small nuclei, or EM radiation that causes and/or results from nuclear reactions
Alpha particle
A helium nucleus without electrons; atomic weight of 4, charge of 2⁺; has small penetrating ability, but can cause much damage
Beta particle
A high-speed electron originating from nucleus; no weight, charge of 1⁻; has a greater penetrating ability than alpha particles, but is not as damaging
Gamma ray
High energy light, also known as EM radiation; has a great degree of penetration and is highly damaging
Radioactive decay
Spontaneous disintegration of unstable nuclei into nuclei and “radiation” which obeys the Laws of Conservation of Mass, Charge, and Energy
Alpha emission
Radioactive decay that gives off an alpha particle; *occurs because too many protons
Beta emission
Radioactive decay that gives off an beta particle (electron); *occurs when too many neutrons because converts a neutron into a proton and electron not in the electron cloud
Positron emission
Radioactive decay that gives off an anti-electron (“positron”); *occurs when too few neutrons because converts proton into neutron and positron
Electron capture
Radioactive decay that captures an electron from the inner orbitals and “collapses” it into the nucleus; *occurs when too few neutrons because converts electron and proton into a neutron; opposite of Beta emission
Spontaneous fission
A process where heavy nuclei (where the number of protons is greater than 89) split spontaneously into several lighter nuclei and energy
Radioactive decay series
A sequence where one radioactive nucleus decays through many steps until a stable nucleus is reached
Nuclear bombardment reactions
When a nucleus is struck by another nucleus or nucleus particle with enough energy to cause rearrangement of nucleons (AKA nuclear transmutations)
Nuclear fission
A nuclear reaction where heavy nucleus splits into smaller nuclei and energy is released
Chain reaction
A self-perpetuating series of nuclear fission reactions caused by the release of more neutrons than the initial number
Critical mass
The minimum amount of fissionable isotopes needed for a sustained chain reaction
Thermonuclear fusion
The combining of two different nuclei together fast enough to overcome EM repulsion and close enough for strong force attraction to create a bigger nucleus, producing a lot of energy
Ionization radiation
When various products of radioactive decay (notably alpha particles, beta particles, and gamma radiation) knock electrons out of molecules to form cation free-radicals; very damaging to organisms
Half-life equation
A(t) = A(0)e^[(-ln(2)/t)(t)]
Binding energy equations
BE = P(p mass) + N(n mass) – mass
BE per nucleon = BE/nucleons*
*nucleons = P + N
Categories: Nuclear Chemistry