MCAT Chem
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amu
1 amu = 1.66 x 10^{27}

mass number
protons + neutrons

E_{photon}
 hf = h (c/)
 planck's constant * frequency
 frequency = speed of light / wavelength

Planck's constant  h
6.63 x 10^{34 }J*s

alpha particle  (He)
 2 protons and 2 neutrons emitted
 Ex: ^{210}_{84}Po > ^{206}_{82}Pb + ^{4}_{2}
 subtracts 4 from mass number
 subtracts 2 from atomic number

beta decay 
^{}
 1 neutron is converted into a proton and an electron.
 proton and electron (electron is emitted)
 Mass number remains the same
 Ex: ^{14}_{6}C > ^{14}_{7}N + ^{0}_{1}e
 Occurs when high neutron to proton ratio
 adds 1 to atomic number

^{+ }decay
 1 proton is converted into a neutron and a positron
 neutron and positron (positron is emitted)
 Mass number remains the same
 Ex: ^{18}_{9}F > ^{18}_{8}O + ^{0}_{+1}e+
 Occurs when high proton to neutron ratio
 subtracts 1 from atomic number

Electron capture
 1 electron is captured to convert a proton into a neutron
 Similar to ^{+} ejection (positron emission)
 Mass number to stay the same
 Ex: ^{51}_{24}Cr + ^{0}_{1}e > ^{51}_{23}V
 Occurs when high proton to neutron ratio
 subtracts 1 from atomic number


mass defect 
m
 total mass of separate nucleons  mass of nucleus
 will always be positive

E_{B }  Einstein's binding energy equation
mc
^{2 }=
m(in amu) x 931.5MeV

In Binding energy 1 kg =
9 x 10^{16 }J

c^{2 } speed of light squared
9 x 10^{16}

Half life  t_{1/2}
 N = N_{0}e^{kt}
 N = N_{0}(1/2)^{t/t1/2 }
 k = (ln 2)/t_{1/2}