D

AILY SCIENCE

 Write the following elements using short hand notation: 1.

Helium 2.

3.

4.

5.

Tin Zinc Chlorine Tungsten

R ADIOACTIVITY Pg. 33

R

ADIOACTIVITY

   Reactions which involve a change in an atom’s nucleus are called nuclear reactions.

Radioactivity- the spontaneous emission of radiation (rays and particles) By emitting radiation, atoms of one element can change into atoms of another element.

   Happens because of unstable nuclei The element undergoing decay is called the parent nuclei New element is called the daughter nuclei

R

ADIOACTIVE

D

ECAY

 Spontaneous process (doesn’t require energy)   Nuclei change until there is a stable product. Half-life- the time it takes for ½ of a radioactive isotope to decay into its stable products.

 Ex. If gallium has a half-life of 68.3 minutes, how much of a 10.0 mg sample is left after 1 half life? After 136.6 minutes? After 3 half-lives?

T

YPES OF

R

ADIATION

 Alpha radiation   Beta radiation-β Gamma radiation- γ

A

LPHA

R

ADIATION

    Particle deflected toward a negatively charged plate Alpha particles ( ) Equivalent to a helium-4 nucleus Decay equation:  Represented by a nuclear equation

B

ETA

D

ECAY

 Deflected toward a positive plate   Fast moving electrons ( ) Beta decay results in the creation of a new atom

G

AMMA

R

ADIATION

 High-energy radiation that possess no mass and are denoted by the symbol 0

0

  Not deflected when passed through a plate Usually accompany alpha decay