The Half-Life of an Element Is 15 Minutes

question 29

Multiple Choice

The half-life of an element is 15 minutes. A sample contains 20,000 atoms of the element. How many atoms of the element will remain after 30 minutes?

• A) 2,000
• B) 5,000
• C) 10,000
• D) 2,500
• E) 1,000

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Definitions:

Clique

A small, exclusive group of individuals; often used in a pejorative sense to describe a group that is unwelcoming to outsiders.

High School Years

The period of education that occurs during adolescence, typically covering grades 9 through 12 in the United States.

Identity

The qualities, beliefs, personality, looks, and/or expressions that make a person (self-identity) or group (particular social category or social group).

Primary Sex Characteristics

The physical features that are directly involved in reproduction, such as the ovaries in females and the testes in males.