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Difficulty: EasyAtomic Structure and Periodic Table

A neutral atom of fluorine has an atomic number of 99 and a mass number of 1919. How many neutrons are contained in the nucleus of this atom?

  1. A
    99
  2. 1010Answer
  3. C
    1919
  4. D
    2828

Answer

The nucleus contains 1010 neutrons.
The mass number (A=19A = 19) is the total number of protons and neutrons in the nucleus. The atomic number (Z=9Z = 9) represents the number of protons. The number of neutrons is determined by subtracting the atomic number from the mass number: 19−9=1019 - 9 = 10.

Step-by-Step Solution

1
Identify the given atomic number and mass number.
Atomic number (ZZ) = 99, Mass number (AA) = 1919.
The atomic number indicates the number of protons, while the mass number represents the sum of protons and neutrons.
2
Apply the subatomic particle calculation formula: Number of Neutrons=Mass Number(A)−Atomic Number(Z)\text{Number of Neutrons} = \text{Mass Number} (A) - \text{Atomic Number} (Z).
19−9=1019 - 9 = 10
Subtracting the number of protons from the total nucleon count yields the number of neutrons.

Key Concept

Subatomic particle calculation using atomic number and mass number
Estimated Time:45s
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Topics

Atomic Structure and Periodic Table

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