Complete Electron Configurations - Questions
The Complete Electron Configurations Concept Builder is comprised of 42 questions. The questions are divided into 18 different Question Groups and spread across three Difficulty Levels. Questions in the same group are rather similar to one another. The Concept Builder is coded to select at random a question from each group until a student is successful with that group of questions.
There are three difficulty levels in the Concept Builder. Those three difficulty levels are differentiated as follows:
- Apprentice Difficulty Level: Question Groups 1-6 ... Identify the correct electron configurations for neutral atoms of elements in Periods 2 and 3.
- Master Difficulty Level: Question Groups 7-12 ... Identify the correct electron configurations for neutral atoms of elements in Periods 3,4, and 5.
- Wizard Difficulty Level: Question Groups 13-18 ... Identify the correct electron configurations for ions of elements in Periods 3 and 4.
The questions from each group are shown below. Teachers are encouraged to view the questions in order to judge which difficulty levels are most appropriate for their classes. We recommend providing students two or more options.
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Complete Electron Configurations
Apprentice Difficulty Level
Question Group 1
Question 1
Identify the complete electron configuration for an atom of the element
lithium (Li):
1s
1
1s
2 1p
1
1s
2 2s
1
1s
2 2p
1
2s
2 2p
1
Question 2
Identify the complete electron configuration for an atom of the element
beryllium (Be):
1s
2
1s
2 1p
2
1s
2 2p
2
1s
2 2s
2
2s
2 2p
2
Question Group 2
Question 3
Identify the complete electron configuration for an atom of the element
boron (B):
1s
2 1p
1
1s
2 2p
1
1s
2 2p
3
1s
2 2s
2 2p
1
1s
2 2s
2 2p
3
Question 4
Identify the complete electron configuration for an atom of the element
carbon (C):
1s
2 2p
2
2s
2 2p
2
1s
2 2p
4
1s
2 2s
2 2p
4
1s
2 2s
2 2p
2
Question Group 3
Question 5
Identify the complete electron configuration for an atom of the element
nitrogen (N):
1s
2 2p
3
2s
2 2p
3
1s
2 2p
3
1s
2 2s
2 2p
5
1s
2 2s
2 2p
3
Question 6
Identify the complete electron configuration for an atom of the element
oxygen (O):
1s
2 2p
4
2s
2 2p
4
1s
2 2p
4
1s
2 2s
2 2p
6
1s
2 2s
2 2p
4
Question 7
Identify the complete electron configuration for an atom of the element
fluorine (F):
1s
2 2p
5
2s
2 2p
5
1s
2 2p
5
1s
2 2s
2 2p
7
1s
2 2s
2 2p
5
Question Group 4
Question 8
Identify the complete electron configuration for an atom of the element
sodium (Na):
1s
2 2s
2 3s
1
1s
2 2p
6 3s
1
1s
2 2p
8 3s
1
2s
2 2p
6 3s
1
1s
2 2s
2 2p
6 3s
1
Question 9
Identify the complete electron configuration for an atom of the element
magnesium (Mg):
1s
2 2s
2 3s
2
1s
2 2p
6 3s
2
1s
2 2p
8 3s
2
2s
2 2p
6 3s
2
1s
2 2s
2 2p
6 3s
2
Question Group 5
Question 10
Identify the complete electron configuration for an atom of the element
aluminum (Al):
1s
2 2p
6 3p
3
1s
2 2s
2 3s
23p
1
1s
2 2s
2 2p
6 3p
3
2s
2 2p
6 3s
2 3p
1
1s
2 2s
2 2p
6 3s
2 3p
1
Question 11
Identify the complete electron configuration for an atom of the element
silicon (Si):
1s
2 2p
6 3p
4
1s
2 2s
2 2p
6 3p
4
2s
2 2p
6 3s
2 3p
2
1s
2 2s
2 3s
23p
2
1s
2 2s
2 2p
6 3s
2 3p
2
Question Group 6
Question 12
Identify the complete electron configuration for an atom of the element
phosphorus (P):
1s
2 2p
6 3p
5
1s
2 2s
2 2p
6 3p
5
2s
2 2p
6 3s
2 3p
3
1s
2 2s
2 3s
23p
3
1s
2 2s
2 2p
6 3s
2 3p
3
Question 13
Identify the complete electron configuration for an atom of the element
sulfur (S):
1s
2 2p
6 3p
6
1s
2 2s
2 2p
6 3p
6
2s
2 2p
6 3s
2 3p
4
1s
2 2s
2 3s
23p
4
1s
2 2s
2 2p
6 3s
2 3p
4
Question 14
Identify the complete electron configuration for an atom of the element
chlorine (Cl):
1s
2 2p
6 3p
7
1s
2 2s
2 2p
6 3p
7
2s
2 2p
6 3s
2 3p
5
1s
2 2s
2 3s
23p
5
1s
2 2s
2 2p
6 3s
2 3p
5
Master Difficulty Level
Question Group 7
Question 15
Identify the complete electron configuration for an atom of the element
potassium (K):
1s
2 2p
8 3p
8 4s
1
1s
2 2s
8 3s
8 4s
1
1s
2 2s
2 2p
6 3s
2 3p
6 3d
1
1s
2 2s
2 2p
6 3s
2 3p
6 4s
1
1s
2 2s
2 2p
6 3s
2 3p
6 3d
10 4s
1
Question 16
Identify the complete electron configuration for an atom of the element
calcium (Ca):
1s
2 2p
8 3p
8 4s
2
1s
2 2s
8 3s
8 4s
2
1s
2 2s
2 2p
6 3s
2 3p
6 3d
2
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2
1s
2 2s
2 2p
6 3s
2 3p
6 3d
10 4s
2
Question Group 8
Question 17
Identify the complete electron configuration for an atom of the element
gallium (Ga):
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
11
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4p
1
1s
2 2s
2 2p
6 3s
2 3p
6 4s
12 4p
1
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
1
1s
2 2s
2 2p
6 3s
2 3p
6 3d
10 4s
2 4p
1
Question 18
Identify the complete electron configuration for an atom of the element
germanium (Ge):
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
12
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4p
2
1s
2 2s
2 2p
6 3s
2 3p
6 4s
12 4p
2
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
2
1s
2 2s
2 2p
6 3s
2 3p
6 3d
10 4s
2 4p
2
Question Group 9
Question 19
Identify the complete electron configuration for an atom of the element
arsenic (As):
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4p
3
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
10 4p
3
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
6 4p
3
1s
2 2s
2 2p
6 3s
2 3p
6 3d
10 4s
2 4p
3
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
3
Question 20
Identify the complete electron configuration for an atom of the element
sellenium (Se):
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4p
4
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
6 4p
4
1s
2 2s
2 2p
6 3s
2 3p
6 3d
10 4s
2 4p
4
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
10 4p
4
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
4
Question 21
Identify the complete electron configuration for an atom of the element
bromine (Br):
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4p
5
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
6 4p
5
1s
2 2s
2 2p
6 3s
2 3p
6 3d
10 4s
2 4p
5
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
10 4p
5
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
5
Question Group 10
Question 22
Identify the complete electron configuration for an atom of the element
tin (Sn):
1s
2 2s
2 2p
6 3s
2 3p
6 3d
10 4s
2 4p
6 4d
10 5s
2 5p
2
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
10 4p
6 5s
2 5d
10 5p
2
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
6 5s
2 4d
10 5p
2
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
6 5s
2 4f
14 4d
10 5p
2
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
6 5s
2 3f
14 4d
10 5p
2
Question 23
Identify the complete electron configuration for an atom of the element
tellurium (Te):
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
10 4p
6 5s
2 5d
10 5p
4
1s
2 2s
2 2p
6 3s
2 3p
6 3d
10 4s
2 4p
6 4d
10 5s
2 5p
4
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
6 5s
2 4d
10 5p
4
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
6 5s
2 4f
14 4d
10 5p
4
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
6 5s
2 3f
14 4d
10 5p
4
Question 24
Identify the complete electron configuration for an atom of the element
iodine (I):
1s
2 2s
2 2p
6 3s
2 3p
6 3d
10 4s
2 4p
6 4d
10 5s
2 5p
5
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
10 4p
6 5s
2 5d
10 5p
5
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
6 5s
2 4d
10 5p
5
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
6 5s
2 3f
14 4d
10 5p
5
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
6 5s
2 4f
14 4d
10 5p
5
Question Group 11
Question 25
Identify the complete electron configuration for an atom of the element
vanadium (V):
1s
2 2s
2 2p
6 3s
2 3p
6 4d
5
1s
2 2s
2 2p
6 3s
2 3p
6 3d
5
1s
2 2s
2 2p
6 3s
2 3p
6 3d
3 4s
2
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
3
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
3
Question 26
Identify the complete electron configuration for an atom of the element
chromium (Cr):
1s
2 2s
2 2p
6 3s
2 3p
6 4d
6
1s
2 2s
2 2p
6 3s
2 3p
6 3d
6
1s
2 2s
2 2p
6 3s
2 3p
6 3d
4 4s
2
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
4
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
4
Question 27
Identify the complete electron configuration for an atom of the element
iron (Fe):
1s
2 2s
2 2p
6 3s
2 3p
6 4d
8
1s
2 2s
2 2p
6 3s
2 3p
6 3d
8
1s
2 2s
2 2p
6 3s
2 3p
6 3d
6 4s
2
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
6
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
6
Question Group 12
Question 28
Identify the complete electron configuration for an atom of the element
nickel (Ni):
1s
2 2s
2 2p
6 3s
2 3p
6 4d
10
1s
2 2s
2 2p
6 3s
2 3p
6 3d
10
1s
2 2s
2 2p
6 3s
2 3p
6 3d
8 4s
2
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
8
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
8
Question 29
Identify the complete electron configuration for an atom of the element
copper (Cu):
1s
2 2s
2 2p
6 3s
2 3p
6 4d
11
1s
2 2s
2 2p
6 3s
2 3p
6 3d
11
1s
2 2s
2 2p
6 3s
2 3p
6 3d
9 4s
2
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
9
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
9
Question 30
Identify the complete electron configuration for an atom of the element
zinc (Zn):
1s
2 2s
2 2p
6 3s
2 3p
6 4d
12
1s
2 2s
2 2p
6 3s
2 3p
6 3d
12
1s
2 2s
2 2p
6 3s
2 3p
6 3d
10
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
10
Wizard Difficulty Level
Question Group 13
Question 31
Identify the complete electron configuration for an ion of the element
sodium (Na+):
1s
2 2s
2 2p
6
1s
2 2s
2 2p
7
2s
2 2p
6 3s
1
1s
2 2s
2 2p
6 3s
1
1s
2 2s
2 2p
6 3s
2
Question 32
Identify the complete electron configuration for an ion of the element
sodium (Mg2+):
1s
2 2s
2 2p
6
1s
2 2s
2 2p
6 3s
2
1s
2 2s
2 2p
6 3s
4
2s
2 2p
6 3s
2 3p
2
1s
2 2s
2 2p
6 3s
2 3p
2
Question Group 14
Question 33
Identify the complete electron configuration for an ion of the element
potassium (K+):
1s
2 2s
2 2p
6 3s
2 3p
6
1s
2 2s
2 2p
6 3s
2 3p
7
2s
2 2p
6 3s
2 3p
6 4s
1
1s
2 2s
2 2p
6 3s
2 3p
6 4s
1
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2
Question 34
Identify the complete electron configuration for an ion of the element
calcium (Ca2+):
1s
2 2s
2 2p
6 3s
2 3p
6
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2
1s
2 2s
2 2p
6 3s
2 3p
6 4s
4
1s
2 2s
2 2p
6 3s
2 4s
2 4p
2
1s
2 2s
2 2p
6 3s
2 4s
2 3d
2
Question Group 15
Question 35
Identify the complete electron configuration for an ion of the element
aluminum (Al3+):
1s
2 2s
2 2p
6
1s
2 2s
2 2p
6 3s
5
1s
2 2s
2 2p
6 3s
2 3p
1
1s
2 2s
2 2p
6 3s
2 3p
4
1s
2 2s
2 2p
6 3s
2 3p
6
Question 36
Identify the complete electron configuration for an ion of the element
phosphorus (P3-):
1s
2 2s
2 2p
6 3s
2
1s
2 2s
2 2p
6
1s
2 2s
2 2p
6 3s
2 3p
6
1s
2 2s
2 2p
6 3s
2 3p
3
1s
2 2s
2 2p
6 3s
2 3d
10 3p
3
Question Group 16
Question 37
Identify the complete electron configuration for an ion of the element
oxygen (O2-):
1s
2 2s
2 2p
6
1s
2 2s
2 2p
4
1s
2 2s
2 2p
2
1s
2 2s
2 2p
6 3s
2 3p
6
1s
2 2s
2 2p
6 3s
2 3p
2
Question 38
Identify the complete electron configuration for an ion of the element
fluorine (F-):
1s
2 2s
2 2p
6
1s
2 2s
2 2p
5
1s
2 2s
2 2p
4
1s
2 2s
2 2p
6 3s
2 3p
6
1s
2 2s
2 2p
6 3s
2 3p
4
Question Group 17
Question 39
Identify the complete electron configuration for an ion of the element
selenium (Se2-):
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
6
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
4
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
2
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
10 4p
4
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
10 4p
6
Question 40
Identify the complete electron configuration for an ion of the element
bromine (Br-):
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
6
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
5
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 3d
10 4p
4
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
10 4p
5
1s
2 2s
2 2p
6 3s
2 3p
6 4s
2 4d
10 4p
6
Question Group 18
Question 41
Identify the complete electron configuration for an ion of the element
sulfur (S2-):
1s
2 2s
2 2p
6 3s
2 3p
6
1s
2 2s
2 2p
6 3s
2 3p
4
1s
2 2s
2 2p
6 3s
2 3p
2
1s
2 2s
2 2p
6 3s
2 3d
10 3p
6
1s
2 2s
2 2p
6 3s
2 3d
10 3p
4
Question 42
Identify the complete electron configuration for an ion of the element
chlorine (Cl-):
1s
2 2s
2 2p
6 3s
2 3p
6
1s
2 2s
2 2p
6 3s
2 3p
5
1s
2 2s
2 2p
6 3s
2 3p
4
1s
2 2s
2 2p
6 3s
2 3d
10 3p
6
1s
2 2s
2 2p
6 3s
2 3d
10 3p
5