Question

In which of the following is the number of neutrons correctly represented? A. fluorine: atomic number 9, mass 19, neutrons 0 B. arsenic: atomic number 33, mass 75, neutrons 108 C. magnesium: atomic number 12, mass 24, neutrons 24 D. uranium: atomic number 92, mass 238, neutrons 146

Answer 1

D. uranium: atomic number 92, mass 238, neutrons 146

238-92=146

Answer 2

Answer: The correct answer is Option D.

Explanation:

Atomic number is defined as the number of protons that are present in an atom. It is represented as Z.

Z = Atomic number = Number of protons

Mass number is defined as the sum of number of protons and neutrons that are present in an atom.  It is represented as A.

A = Mass number = Number of protons + Number of neutrons

For the given options:

• Option A: Fluorine

Atomic number = 9

Mass number = 19

Number of neutrons = 19 - 9 = 10

Thus, the number of neutrons are not represented correctly.

• Option B: Arsenic

Atomic number = 33

Mass number = 75

Number of neutrons = 75 - 33 = 42

Thus, the number of neutrons are not represented correctly.

• Option C: Magnesium

Atomic number = 12

Mass number = 24

Number of neutrons = 24 - 12 = 12

Thus, the number of neutrons are not represented correctly.

• Option D: Uranium

Atomic number = 92

Mass number = 238

Number of neutrons = 238 - 92 = 146

Thus, the number of neutrons are represented correctly.

Hence, the correct answer is Option D.