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MDCAT
Chemistry
2021

Chemistry · Atomic Structure

Work through this past-paper style MCQ, then read the full explanation. Practice more chemistry questions on mMCQ with adaptive practice and topic analytics.

Question

How many electrons can occupy in 7th energy level of an atom? Calculate by using 2n2 formula.  

Options
  • A

    24  

  • B

    5

  • C

    72

  • D

    98  

Explanation

Equation 2n² gives the maximum number of Electrons a shell can contain. So, we are asked to calculate the number of Electrons on the 7th energy level, replace n of the equation with 7 and calculate the number of Electrons. Remember, do not multiply 2 with 7 first, you have to take the square of 7 first and then multiply the calculated value with 2. You will get 98.

      = 2n² = 2 × (7)² = 2 × 49 = 98

Equation 2n² gives the maximum number of electrons a shell can contain. So, we are asked to calculate the number of electrons on the 7th energy level, replace n of the equation with 7 and calculate the number of Electrons. Remember, do not multiply 2 with 7 first, you have to take the square of 7 first and then multiply the calculated value with 2. You will get 98.
= 2n² = 2 × (7)² = 2 × 49 = 98
 

Equation 2n² gives the maximum number of electrons a shell can contain. So, we are asked to calculate the number of electrons on the 7th energy level, replace n of the equation with 7 and calculate the number of Electrons. Remember, do not multiply 2 with 7 first, you have to take the square of 7 first and then multiply the calculated value with 2. You will get 98.
= 2n² = 2 × (7)² = 2 × 49 = 98
 

Equation 2n² gives the maximum number of electrons a shell can contain. So, we are asked to calculate the number of electrons on the 7th energy level, replace n of the equation with 7 and calculate the number of Electrons. Remember, do not multiply 2 with 7 first, you have to take the square of 7 first and then multiply the calculated value with 2. You will get 98.
= 2n² = 2 × (7)² = 2 × 49 = 98
 

Equation 2n² gives the maximum number of electrons a shell can contain. So, we are asked to calculate the number of electrons on the 7th energy level, replace n of the equation with 7 and calculate the number of Electrons. Remember, do not multiply 2 with 7 first, you have to take the square of 7 first and then multiply the calculated value with 2. You will get 98.

      = 2n² = 2 × (7)² = 2 × 49 = 98

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Tagged under Chemistry · Atomic Structure · 2021