Chem 121
Worksheet – Ch. 2.1 – 2.6
You may work with a partner and use your textbook and a calculator. This worksheet will not be
graded, but you may want to write out all your work for practice and future reference. Make
sure your answer has the correct units and number of significant figures.
1. Give the chemical symbol for the following elements
a. tin
b. potassium
c. phosphorus
d. sodium
e. nitrogen
2. Match the subatomic particle with its charge.
Electron
+1
Neutron
-1
Proton
0
3. How many protons are in the nucleus of gold?
4. Bromine occurs as about a 50:50 mix of two isotopes, Br-79 and Br-81. How many neutrons
are in the nucleus of each isotope?
5. Write out the electronic configurations of the following elements. Write the configurations
out both in full detail and with noble gas notation.
a. iron
b. magnesium
c. silicon
d. iodine
e. boron