Nuclear Chemistry

Nuclear Chemistry Remember that an element is defined by the number of protons in the nucleus. If I say the Oxygen-18 Isotope, I am referring to the Atomic Mass as 18. This can be written as 18O. Remember, the Atomic Mass is the number of protons and neutrons.

Nuclear Chemistry Many Isotopes are radioactive. Radioactivity is the spontaneous decomposition of nuclei. Spontaneous means they do it alone, with no required input of energy from us.

Alpha Decay Alpha particle (4He) is ejected. Only happens when Z > 83 222Ra  4He + 218Rn + (γ rays) The sums of nucleons is conserved!

What isotope is formed from the Alpha decay of Bi-211? iRespond Question F Multiple Choice A.) Tl-207 B.) Tl-215 C.) At-207 D.) At-215 E.)

Beta Decays Three major types of beta decay: Negatron Positron Megatron (just kidding!) Electron Capture

Negatron Decay Changes a neutron into a proton Produces a negatron and antineutrino Occurs when n/p ratio is too high 24Na  24Mg + β- + ν-

What isotope will be formed from the negatron decay of Ag-116? iRespond Question F Multiple Choice A.) Pd-117 B.) Pd-115 C.) Ag-115 D.) Cd-116 E.)

Positron Decay Changes a proton into a neutron Produces a positron, neutrino, and occasionally a gamma ray Occurs when n/p ratio is too low 45Ti  45Sc + β+ + ν + (γ rays)*

What isotope will be formed from the positron decay of Na-22? iRespond Question F Multiple Choice A.) Ne-21 B.) Ne-22 C.) Mg-21 D.) Mg-22 E.)

Positronium When a positron is ejected from the nucleus it can encounter an electron. Since they have opposite charges, they attract and form Positronium (Ps). Lasts from 1.25 x 10-14 s to 1.1 x 10-9 s until annihilation

Annihilation Eventually (like really quickly) the two particles collide. This is the collision of a particle with its antiparticle which turns matter into energy. This is where the γ rays come from

201Hg + -1e  201Ag + γ + ν + (X-Ray or Auger electron) Electron Capture Occurs when n/p ratio is too low. Steals an orbital electron, collides with a proton turning it into a neutron. 201Hg + -1e  201Ag + γ + ν + (X-Ray or Auger electron)

What isotope will be formed from the electron capture decay of As-73? iRespond Question F Multiple Choice A.) Se-74 B.) Se-73 C.) Ge-73 D.) Ge-74 E.)

Gamma Decay Atoms at a higher energy level can release that energy via a gamma ray. 110mAg  110Ag + γ M = metastable state, a somewhat stable equilibrium at a higher energy level.

Predicting Decay Method Alpha: BIG (Z>83) Atoms! Negatron: n/p ratio too high Positron: n/p ratio too low Gamma: Metastable state.

Predict the decay method that the Si-27 isotope undergo. iRespond Question F Multiple Choice A.) Alpha B.) Negatron C.) Positron D.) Gamma E.)

Predict the decay method that the C-14 isotope undergo. iRespond Question F Multiple Choice A.) Alpha B.) Negatron C.) Positron D.) Gamma E.)

Predict the decay method that the Fr-223 isotope undergo. iRespond Question F Multiple Choice A.) Alpha B.) Negatron C.) Positron D.) Gamma E.)

Predict the decay method that the O-18 isotope undergo. iRespond Question F Multiple Choice A.) Alpha B.) Negatron C.) Positron D.) Gamma E.)