!
Name:
Block
Date
Section 4.3 Electron Configurations
Part 1
True or False : If the statement is true, write “true.” If it is false, write the word needed to replace the underlined
word that would make it true.
1
The Pauli exclusion principle states that an orbital can hold a maximum of 2 electrons.
2
The sum of the superscripts in an electron configuration represents the total number of
neutrons in the atom.
3
Another way of stating the aufbau principle is that electrons are added one at a time to
the highest energy orbitals available until all the electrons of the atom have been
accounted for.
4
In an orbital diagram, arrows are used to indicate the velocity of an electron.
5
The ground state is the most stable energy state of an atom.
6
According to Hundʼs rule, electrons occupy the orbitals of a sublevel such that there will
always be a maximum number of paired electrons.
Part 2
carbon
6C
!
1s!
⇄
Example
⇄
Draw labeled orbital diagrams for each of the elements below:
↑
↑
!
2s!
!
2p !
3s!
3p ! !
4s
1 magnesium
!
1s!
!
2s!
!
2p !
3s!
3p ! !
4s
2
oxygen
!
1s!
!
2s!
!
2p !
3s!
3p ! !
4s
3
calcium
!
1s!
!
2s!
!
2p !
3s!
3p ! !
4s
4
argon
!
1s!
!
2s!
!
2p !
3s!
3p ! !
4s
6 phosphorus
!
1s!
!
2s!
!
2p !
3s!
3p ! !
4s
7
!
1s!
!
2s!
!
2p !
3s!
3p ! !
4s
silicon
1
Part 3
Write the electron configurations for each of the following elements and determine the number
of unpaired electrons.
Electron Configuration
1
potassium
2
cobalt
3
silicon
4
lithium
5
iridium
6
selenium
7
bismuth
8
vanadium
9
sulfur
10
mercury
Number of
unpaired electrons
Part 4
Identify the element by the electron configuration given and determine the number of unpaired
electrons.
element
Electron Configuration
1
1s22s22p3
2
1s22s22p63s23p3
3
1s22s22p63s23p64s23d1
4
1s22s22p63s23p64s23d10
5
1s22s22p63s23p64s23d104p65s24d105p66s24f145d6
Number of
unpaired electrons
2
Part 5
Noble Gas Notation
ex
bromine
1
cobalt
2
potassium
3
silicon
4
nickel
5
manganese
6
gallium
7
krypton
8
zinc
9
mercury
10
Ca+
11
Si2-
12
Cu+
13
Fe3+
14
Cs+
15
Sn4+
16
P3-
"
Complete the following table
Symbol
with
atomic
number
Number of
electrons
35Br
35
20Ca+
20-1=19
Noble gas notation
Number
of
unpaired
electrons
[Ar]4s23d104p5
1
[Ar]4s1
1
3
In the space provided, write the letter of the correct term or phrase that best completes each statement
or best answers each question.
_____ 1. The statement that no two electrons in the same atom can have the same four quantum
numbers is a restatement of
a. Bohr’s law.
c. the Aufbau principle.
b. Hund’s rule.
d. the Pauli exclusion principle.
_____ 2. According to the Aufbau principle, which of the following sublevels is lowest in energy?
a. 3d
c. 4p
b. 4s
d. 5s
_____ 3. In a ground-state hydrogen atom in which orbital is the electron?
a. 1s
c. 2p
b. 2s
d. 3s
_____ 4. How many electrons are present in an atom of calcium that has the electron configuration
1s22s22p63s23p64s2?
a. 6
c. 20
b. 16
d. 36
_____ 5. The ground-state electron configuration of neon is 1s22s22p6 In this arrangement, how many
of neon’s p orbitals are completely filled?
a. 1
c. 3
b. 2
d. 6
_____ 6. Oxygen has an electron configuration of 1s22s22p4 In this arrangement, how many inner-shell
electrons does oxygen have?
a. 1
c. 4
b. 2
d. 8
_____ 7. Which of the following is a noble gas?
a. carbon
c. sodium
b. oxygen
d. neon
_____ 8. The noble-gas notation for the electron configuration of bromine is [Ar] 3d104s24p5. How
many unpaired electrons are there in an atom of bromine in the ground state?
a. 0
c. 3
b. 1
d. 5
_____ 9. A ground-state atom of which element has one electron in its fourth and outermost main
energy level?
a. K
c. B
b. Na
d. Ga
_____10. Separating unpaired electrons into as many orbitals as possible
a. places the electrons farther from the nucleus.
b. results in more valence electrons.
c. minimizes the repulsion between electrons.
d. produces a greater spin quantum number.
4