Name: __________________________ Mr. Hauptman
HW # 17
1. Determine the number of protons, electrons, and neutrons for isotopes a. through f. in the table below. Name each
isotope, and write its symbol.
Element
a. Neon
b. Calcium
c. Oxygen
d. Iron
e. Zinc
f. Mercury
Atomic
number
Mass number
10
20
8
26
30
80
22
46
17
57
64
204
Protons
Electrons
Neutrons
Name
Symbol
2. Boron has two naturally occurring isotopes: boron-10(abundance= 19.8%, mass =10.013 amu), boron-11(abundance=
80.2%, mass=11.009 amu). Calculate the atomic mass of boron.
3. Helium has two naturally occurring isotopes, helium-3 and helium-4. The atomic mass of helium is 4.003 amu. Which
isotope is more abundant in nature? Explain.
4.Calculate the atomic mass of magnesium. The three magnesium isotopes have atomic masses and relative
abundances of 23.985 amu (78.99%), 24.986 amu (10.00%), and 25.982 amu (11.01%).