Do Now:

1. Have a cookie. 2. Tape the objectives into your

notebook.3. Leave the notebook out to

take notes.

Isotopes&

Radiation

Objective

• Explain how isotopes of the same element are different from each other. Explain what they have in common.

• Isotopes of the same element have the same number of p+, but different numbers of n0. Therefore, they also have different masses.

Isotopes of HydrogenIsotope Symbol p+ n0 mass

Hydrogen-1 11H or 1H 1 0 1

Hydrogen-2(deuterium)

21H or 2H 1 1 2

Hydrogen-3(tritium)

31H or 3H 1 2 3

Deuterium and tritium have unstable nuclei and are radioactive.

Isotopes – you don’t need to write this

• You do not have to memorize which isotopes exist for each element.

• You do not have to memorize the % of each isotope that exists.

• You should be able to draw isotopes and fill in tables like the ones you have with given information and to identify isotope symbols.

Understanding Isotope SymbolsIsotope Symbol p+ n0 mass

Helium-3 32He or 3He 2 1 3

Helium-4 42He or 4He

Sulfur-35 3516S or 35S

6 66 13

8 14

2 2 4

16 19 35Carbon-12 12

6C or 12C 12Carbon-13 13

6C or 13C 7Carbon-14 14

6C or 14C 6

Calculating Atomic mass

• Atomic mass Cl= (.7576 x 35) + (.2424 x37)= 35.5

Isotope Mass Number % Natural Abundance

Chlorine-35 35 75.76%Chlorine-37 37 24.24%

Isotopes

• Some isotopes have unstable nuclei, which fall apart and release radiation.

• Some isotopes are stable, and do not release radiation.

Understanding Isotope SymbolsIsotope Symbol p+ n0 mass

Helium-3 32He or 3He 2 1 3

Helium-4 42He or 4He 2 2 4

Sulfur-35 3516S or 35S 16 19 35

Carbon-12 126C or 12C 6 6 12

Carbon-13 136C or 13C 6 7 13

Carbon-14 146C or 14C 6 8 14

Forms of Radioactive DecayAlpha

Beta

Gamma – The release of high energy electromagnetic waves from the nucleus

Half Life

• The time required for half of the atoms of a radioactive nuclide to decay.

• The half life of Radium- 226 is 1599 years.

• In 1599 years half of a given amount of Radium will decay.

We Are Exposed to Radiation Daily

Radiation Detection

• There are ways to detect the amount of ionizing radiation– Radiation Badges– Geiger Counters• Beta particles and gamma rays

OLD Orange/Red Fiestaware

• The red paint has uranium oxide which is radio active.

• Gives off beta and gamma radiation.

• Does not transfer to foods unless you eat the paint. (thus the napkin on the plate)

Some Useful Radioisotopes

• 14C for tracking sugars through an organism as part of C6H12O6

• 35S for tracking proteins or DNA• 32P for tracking DNA• 125I for tracking proteins

A gamma ray detector scan of a normal human heart, obtained following intravenous injection of the radioisotope thallium-201, a gamma emitter. The donut-shaped pink and red area represents uptake of the radioisotope by healthy heart muscles.

Radioisotope scanning

Positron emission tomography (PET). A patient is injected with a solution of a radiolabeled compound that quickly moves to the brain. Radioactive nuclei within the compound emit positrons. PET images of the human brain showing areas active in obsessive-compulsive behavior. The red and yellow areas are the active areas, as indicated by blood flow detected by the radioactive tracer.

Nuclear Fission

Draw atoms of these isotopes:12C and 14

6C