General Chemistry Flashcards
Alpha decay
Emits a positively charged particle consisting of two neutrons and two protons
Beta- decay
Most common type of beta decay
Occurs when an unstable nucleus contains too many neutrons, a neutron is converted into a proton and an electron is ejected
Beta+ decay
Also known as positron emission
Occurs when an unstable nucleus has too few neutrons, it converts a proton into a neutron and ejects a positron
Electron capture
Another form of beta decay
Occurs when an unstable nucleus has too few neutrons, will capture an electron from the closest electron shell and use it to convert a proton into a neutron. Causes the atomic number to go down while the mass number stays the same
Gamma decay
A nucleus in an excited energy state (usually after alpha or beta decay) will “relax” to ground state by emitting energy as gamma photons (no mass or charge)
Nuclear binding energy formula
Einstein’s equation
E=mc^2
c = speed of light = 3x10^8 m/s
Energy/frequency/wavelength formula
Ephoton=hf=h(c/y)
h=Planck’s constant=6.63x10^-34 Jxs
c=speed of light = 3x10^8 m/s
y = wavelength
Bohr model
Electrons assume discrete energies. Electron is in one of a limited number of circular orbits. Bohr atom is one with only one electron
Aufbau principle
Electrons occupy the lowest electron orbital available
Hund’s rule
Electrons in the same subshell occupy available orbitals singly before pairing up
Pauli exclusion principle
There can be no more than 2e- in any given orbital
Diamagnetic
An atom that has all of its electrons spin paired; would be repelled by an external magnetic field
Paramagnetic
Not all electrons are spin-paired, are attracted to external magnetic fields
Atomic radius periodic trend
Increases right to left and down the periodic table
Ionization energy periodic trend
Increases up and left to right the periodic table
