Name ______________________

You should be able to complete this worksheet after studying Sections 4.1 – 4.3 in your textbook. This will let you see if you understand the terms we use to describe the structure of an atom.

1) What are the three major subatomic particles’ masses (amu’s and grams), charge (elementary charges), and location (general vicinity)?

2) Fill in the cells.

Symbol	Atomic Number (Z)	Mass Number (A)	# of Protons	# of Neutrons	# of Electrons	Atomic Mass (amu)
a. 3^7Li
b. 1^1H
c. 19^39K^1+
d. ^15O^2-
e. 13^27 ^3+
f.	30	65			28
g.			2	2	2
h.	17			18	18
i.	14			14	10
j. 92^238U

Is a. the most common isotope of Li? ________ Is d. the most common isotope of O? ___________ Briefly explain your reasoning.

3) Use the data in the table below to find the atomic mass of each element. Compare your calculation to the atomic mass listed on your periodic table.

* Natural Percent Abundance of Some Elements

Name	Symbol	Natural Percent Abundance	Mass (AMU)	Calculated Average Atomic Mass	Accepted Average Atomic Mass
Hydrogen	^1H ^2H ^3H	99.985 .015 negligible	1.0078 2.0141 3.0160
Oxygen	^16O ^17O ^18O	99.759 .037 .204	15.995 16.995 17.999
Chlorine	^35Cl ^37Cl	75.77 24.23	34.969 36.966

* Source: Prentice Hall Chemistry (P. 114)

Show your work in the space provided below.