Ch. 10.3 - Radioactive Dating

Ch. 10.3

Radioactive Dating

Multiple Choice

Radioactive decay is a process where an element

• breaks down and releases particles and energy, eventually turning into atoms of another element

• undergoes a chemical reaction and forms a new compound, resulting in new chemical properties

• gains more electrons and becomes an ion, resulting in an atom with an electric charge

• is converted into glucose and water, being able to be absorbed by plants as food

Multiple Choice

True or False? The composition of a rock containing a radioactive element will change over time by breaking down and turning into a new more stable element.

• True

• False

Multiple Choice

A radioactive element's rate of decay is like a ticking of a clock because

• it breaks down sporadically and unpredictably

• it breaks down at a constant rate, like a clock ticks at a constant rate

• it will eventually stop breaking down at midnight, or 12 AM

• It can be used in a clock to make the clock cheaper and more affordable

Open Ended

Why is it difficult to determine the absolute age of a sedimentary rock?

Multiple Choice

A geologist finds a fossile in a layer of sedimentary rock that lies in between two igneous extrusions. The geologist can determine the age of the fossil by

• looking at the fossil and seeing what type of animal it was

• finding the absolute age of the sedimentary rock layer and then estimating the age of the fossil to be younger

• finding the relative age of the igneous extrusions and then determining if the fossil is the same age

• finding the absolute age of the igneous extrusions and estimating the age of the fossil to be somewhere between.

Fill in the Blank

If a radioactive element starts with a composition that is 100%, what percentage of the element will be left over after 7 half lives?

(Round your answer to two places after the decimal)

= _________ %