Now remember, an atom possesses shells. Each shell for a given atom has a maximum number of electrons it can hold. So, when only the shell number n is given, the number of electrons is equal to 2×n2. If we're looking here at the first shell where n equals 1, that would mean that we have 2×12, which is 2 times 1, so the first shell can hold a maximum of 2 electrons. The second shell here, n equals 2, that'd be 2×n2, which would be 2 times 4, which equals 8 electrons max that it can hold. So, remember, if they only give you the n value, then you can use 2×n2 to determine the total number of electrons found within that given shell.
2. Atoms and the Periodic Table
Electronic Structure: Number of Electrons
2. Atoms and the Periodic Table
Electronic Structure: Number of Electrons - Online Tutor, Practice Problems & Exam Prep
Shell number can give the quantity of electrons within a given atom.
Number of Electrons within a Shell
1
concept
Electronic Structure: Number of Electrons Concept 1
Video duration:
46sVideo transcript
2
example
Electronic Structure: Number of Electrons Example 1
Video duration:
38sVideo transcript
Here we have to determine how many electrons can be found in the 7th shell of an atom. So remember, the 7th shell corresponds to n=7. When we only know the shell number, the number of electrons is just equal to 2×n2. So that will equal 2×72. 72 is 49, and multiplying it by 2 means that we can have theoretically up to 98 electrons within the seventh shell of a given atom. So that would mean that option d would be our correct answer.
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Problem
ProblemTheoretically, how many total electrons can be found in the 6th shell of an atom?
A
18
B
72
C
8
D
32
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Problem
ProblemAn element possesses 4 energy levels. How many total electrons can it theoretically hold?
A
72
B
100
C
110
D
60
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