Summary Week 2 Assignment

Week 2 Assignment (15 points):



1. In terms of electrons, what is an excited state? Give an example of an electron configuration for
an excited state. (1 points)
a. An electron enters its excited state when it temporarily occupies an energy state that is
greater than it’s ground state. An example of this would be if Oxygen, the electron
configuration of which is 1s22s22p4, the excited state configuration would look like
1s22s22p23s1.




2. Give the ground state electron configuration for Fe. (1 points)
a. 1s22s22p63s23p64s23d6.




3. What is a valance electron? How many valance electrons does Si have? (1 points)
a. Valance electrons are electrons that reside in the outer shell of an atom and can
participate in the forming of bonds with other atoms. Si has 4 valance electrons.




4. What is the shorthand electron configuration of a potassium ion (K +)? (1 points)
a. The shorthand electron configuration of a potassium ion is [Ar]4s 1.




5. Give the chemical formula (with charge) for each of the following polyatomic ions: (0.5 points
each, 2.5 points total)
a. Phosphate – PO43-
b. Ammonium – NH4+
c. Sulfate – SO42-
d. Hydroxide – OH-
e. Carbonate – CO32-




6. What is an Ion and what is the difference between an anion and a cation? (1 points)