Chem Nuclear Decay

A

Mass Number (found on periodic table). number of protons and neutrons in nucleus

Z

Atomic Number (number on bottom of isotope, but top on periodic table). Gives number of protons in nucleus.

N=A-Z

number of neutrons

Alpha Decay

emits alpha particles (2 protons and 2 neutrons, or helium-4 nucleus). common in heavy elements like uranium, thorium, radium

Alpha Decay causes

a decrease in atomic number by 2 and mass number by 4

Beta Decay

β-. neutron is transformed into a proton or an electron.

Beta Decay causes

an increase in atomic number by one, no mass number change

N:Z ratio is too high (neutron rich)

When does beta decay take place?

Positron Emission/Electron Caputre

β+. Proton is converted into a neutron or a positron

Positron Emission causes

a decrease in atomic number by one, but no change in mass number

N:Z ratio is too low (neutron-deficient)

When does positron decay take place?

Gamma Decay

no change in # of protons or neutrons, only energy state of nucleus changes