-Reactions are accompanied by relatively large changes in energy and measurable changes in mass

-reaction rates depend only on number of nuclei and rarely based on the compound in which it occurs

atoms with the characteristic number of protons of the element but different numbers of neutrons

-in nature, the isotopes of the element are present in specific proportions

Helium 2+ ion expelled

change in mass is -4

change in protons is -2

change in charge is -2
-Every element beyond Bi(z = 83) is radioactive and exhibits alpha decay

nucleus changes to a proton and a negative beta particle

change in mass = 0

change in protons = +1

change in charge = -1

a proton changes to a neutron and a positive beta particle

change in mass = 0

change in protons = -1

change in charge = +1

An electron and proton are changed into a neutron

change in mass = 0

change in proton = -1

change in charge = +1

-elements with an even z usually have a larger number of stable nuclides than elements with and odd z.

-only four nuclides with odd N and odd z are stable: H(2/1), Li(6/3),B(10/5),N(14/7)

-Neutron-rich nuclides= undergo beta decay

-Proton rich nuclides= undergo beta emission or electron capture

-Heavy nuclides(Z>83) undergo Alpha decay

-larger the decay constant, the higher decay rate

A= (-delta nuclei)/(delta t) = k*nuclei

*ln(nuclei(t)/nuclei(0)) = -kt

*nuclei(t) = nuclei(0)*e^(-kt)

It is a first-order process

-in the case of nuclear decay the number of nuclei is considered rather than their concentrations

-the number of nuclei remaining is halved after each half-life

-t(1/2) = ln2/k

*dependent of number of nuclei

A(t) = A(0)*e^(-k*t)

E = mc^2

Delta(E) = Delta(m)*c^2

The energy an electron acquires when it moves thru a delta(V) of 1 volt

1 eV = 1.602E-19J