HONORS PHYSICAL SCIENCE
Orbital Diagrams and Electron Configurations
1. What is the Aufbau Principle?
Orbitals fill from lowest energy to highest energy
2. How does this principle apply to an atom with multiple electrons?
Electrons will always fill lower energy levels first before any of the higher energy levels
are filled
3. What is Hund’s Rule?
In sublevels that contain multiple orbitals, these orbitals all have the same energy,
electrons will distribute themselves as evenly as possible. Each orbital will get at least
one electron before any orbital gets two.
4. How does this apply to the orbital diagram for nitrogen?
In the 2p sublevel, each of the three p orbitals will get a single electron
5. What is the Pauli Exclusion Principle?
No two electrons can have the same set of quantum numbers. For two electrons in the
same orbital, they must have different “spin”
6. What quantum number accounts for the Pauli Exclusion Principle?
Spin quantum number
7. Write the orbital diagrams and electron configurations for the following elements:
a. Nitrogen – 1s filled (one arrow up, one arrow down), 2s filled, three 2p orbitals each with one arrow
b. Silicon – 1s filled, 2s filled, three 2p filled, 3s filled, three 3p orbitals, but only two
have one electron – the third is empty
c. Calcium – 1s filled, 2s filled, three 2p filled, 3s filled, three 3p filled, 4s filled
d. Arsenic – 1s filled, 2s filled, three 2p filled, 3s filled, three 3p filled, 4s filled, five 3d
filled, three 4p – each with one electron
8. Write the electron configurations for unnamed atoms containing the following number of
electrons:
a. 3 – 1s22s1
b. 6 – 1s22s22p2
c. 8 – 1s22s22p4
d. 13 – 1s22s22p63s23p1
9. What is the highest occupied principal energy level for the following elements?
a. He n=1
b. Be n=2
c. Al n=3
d. Ca n=4
e. Sn n=5
10. What is the highest occupied orbital for the following elements?
a. He 1s
b. Be 2s
c. Al 3p
d. Ca 4s
e. Sn 5p
11. The electron configuration for oxygen is 1s22s22p4. Use this information to answer the
following questions:
a. How many electrons does oxygen have? 8
b. What is the atomic number of oxygen? 8
c. Write the orbital diagram for oxygen. 1s filled, 2s filled, three 2p – one has two
electrons (one up, one down) and the other two have one electron each
d. How many unpaired electrons does oxygen have? 2
e. What is the highest occupied energy sublevel in oxygen? 2p
f. How many inner shell electrons does oxygen have? 2
g. How many valence electrons does oxygen have? 6
12. The electron configuration for phosphorus is 1s22s22p63s23p3. Use this information to
answer the following questions:
a. How many electrons does phosphorus have? 15
b. What is the atomic number of phosphorus? 15
c. Write the orbital diagram for phosphorus. 1s filled, 2s filled, three 2p filled, 3s
filled, three 3p – each with one electron
d. How many unpaired electrons does phosphorus have? 3
e. What is the highest occupied energy sublevel in phosphorus? 3p
f. How many inner shell electrons does phosphorus have? 10
g. How many valence electrons does phosphorus have? 5