Biology Exam Chapters 1&2 Flashcards Preview

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Flashcards in Biology Exam Chapters 1&2 Deck (10):
1

An element is a substance that cannot be separated into simpler parts by

chemical reactions
(ordinary chemical means)

2

Over 96% of an organisms weight is made up of four elements

oxygen, carbon, hydrogen, and nitrogen

3

The three main parts of an atom are the

protons, neutrons, and electrons

4

The ______________ are in the nucleus and the ________________ occupy energy levels and orbitals around the nucleus

protons and neutrons
electrons

5

The number of protons in a atom is called the

atomic number

6

The total number of protons and neutrons in an atom is referred to as the

atomic mass

7

An atomic mass unit (amu) is also called a

dalton

8

The _____________________________ of isotopes vary, but the _________________ remains constant

atomic mass (or number of neutrons)
atomic number (or number of protons)

9

Unstable isotopes that emit radiation when they decay are termed

radioisotopes

10

electrons with the same energy compromise an

electron shell (or energy level)