1B 20.1 Nuclear Decay - Prof Rose-Seisa PDF

Preview

Summary

Prof Rose-Seisa...

Description

C h. 20, Nu cl ear C hem i stry |1

Ch. 20.1: Nuclear Decay CHEMV01B, General Chemistry II Learning Outcomes: By the end of this lecture you should be able to: (1) Identify the five types of radioactive (nuclear) decay. (2) Write balanced nuclear reactions.

Equations and Constants none

(1) Nuclear Decay The three subatomic particles in an atom determine its different properties. • • •

Proton (p+): positive charge, determines the element Neutron (n): neutral, determines the isotope Electron (e-): negative, determines the ion (charge)

The subatomic composition of an atom is given in its atomic notation. A Z chemical

•

•

symbol

ionic charge

Mass number (A): sum of protons + neutrons ALWAYS a whole number NOT found on the periodic table Atomic Number (Z): number of protons UNIQUE to each element

Diagram:

•

Atomic mass: weighted average of all isotopes of an element

Different isotopes (N/Z) have different stabilities. Unstable isotopes (nuclei) will undergo decay (lose protons, neutrons, and/or electrons) to become stable.

C h. 20, Nu cl ear C hem i stry |2

(2) Nuclear Decay and Nuclear Reactions (1) Alpha Decay •

Alpha particle:

•

Nuclear equation: balances subatomic particles in a reaction

Ex. 1) Write the balanced nuclear equation for the alpha decay of radon-222.

(2) Beta Decay •

Beta particle:

Formed from:

Ex. 2) Write the nuclear equation for the beta decay of iodine-131.

(3) Gamma Radiation •

Gamma particle:

(4) Positron Emission •

Positron:

C h. 20, Nu cl ear C hem i stry |3

Ex. 3) Write the equation for the positron emission of carbon-11.

(5) Electron Capture •

Electron/beta-particle:

Formed from:

Ex. 4) Write the equation for the electron capture of rubidium-81.

Ex. 5) Write the nuclear equations for: (a)

215

Bi →

83

(b) (c)

212

Fr +

87

215 84Po + 0 205 → 1β + 88 Ra

→

212 86Rn...