Biology Exam Chapters 1&2

Question 1

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

Answer 1

chemical reactions

ordinary chemical means

Question 2

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

Answer 2

oxygen, carbon, hydrogen, and nitrogen

Question 3

The three main parts of an atom are the

Answer 3

protons, neutrons, and electrons

Question 4

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

Answer 4

protons and neutrons

electrons

Question 5

The number of protons in a atom is called the

Answer 5

atomic number

Question 6

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

Answer 6

atomic mass

Question 7

An atomic mass unit (amu) is also called a

Answer 7

dalton

Question 8

The _____________________________ of isotopes vary, but the _________________ remains constant

Answer 8

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

Question 9

Unstable isotopes that emit radiation when they decay are termed

Answer 9

radioisotopes

Question 10

electrons with the same energy compromise an

Answer 10

electron shell (or energy level)