Nuclear Chemistry

electrons

part of atom most a part of chemical reactions

nucleus

part of atom most a part of nuclear reactions

strong nuclear force

a powerful force of attraction that acts on the neutrons and protons in the nucleus, holding them together

Henri Becquerel

discovered radioactivity accidentally from the effect of uranium salts on photographic plates

Marie and Pierre Curie

discovered the elements polonium and radium and described the process of radioactivity

Ernest Rutherford (nature of radioactivity)

discovered alpha, beta and gamma radiation

alpha particle

a type of nuclear radiation consisting of two protons and two neutrons; has a positive charge

beta particle

a high-speed electron emitted in the decay of a radioactive isotope

gamma radiation

a type of nuclear radiation made of high-energy waves

nuclear decay

spontaneous change in the nucleus of an atom that emits nuclear radiation

stability of atoms

most atoms are incredibly stable (have been around "since the beginning")

unstable isotopes

radioactive isotopes that emit energetic particles, alpha and beta waves; the energy from atomic fragments is called radiation

what makes an isotope unstable?

having too many or too few neutrons compared to the number of electrons

it increases

what happens to the neutron to proton ratio as elements get larger?

alpha particle (properties)

identity = helium nuclei; composition 2 protons and 2 neutrons; charge 2+; penetration ability = low; mass = 4

atomic number = 2

beta particle (properties)

identity = high speed electron; charge = -1; penetrating ability = moderate; mass = 0; atomic number = -1

Np-237

what will Am-241 become if it undergoes alpha decay?

N-14

What will C-14 become if it undergoes beta decay?

fission (definition)

When one larger nucleus splits into two lighter nuclei. Process releases energy.

nuclear reactor or nuclear bomb

where does fission take place?

fusion (definition)

combining small nuclei to make a larger nucleus

-but high temperatures needed to overcome repulsion of the positive nuclei

sun and stars or hydrogen bomb

where does fusion take place

half-life

the time it takes for half of a radioactive sample to decay

4 half-lives decays to what percentage of the original?

1/2 x 1/2 x 1/2 x 1/2 = 6.25%

Rontgen

discovered xrays in 1895 when experimenting with cathode rays