A neutral atom of sodium has an atomic number of 11 and a mass number of 23. What is the t… — Armed Services Vocational Aptitude Battery (ASVAB)

A neutral atom of sodium has an atomic number of $11$ and a mass number of $23$ . What is the total number of neutrons present in the nucleus of this atom?

A
$11$
$12$ Answer
C
$23$
D
$34$

Answer

12

neutrons

The mass number (

23

) is the total count of protons and neutrons in the nucleus, and the atomic number (

11

) is the number of protons. Subtracting the atomic number from the mass number (

23 - 11 = 12

) yields the exact number of neutrons.

Step-by-Step Solution

Identify the number of protons and the total nucleon count from the given values.

Atomic number (

Z

) =

11

(protons), Mass number (

A

) =

23

(protons + neutrons)

The atomic number defines the number of protons, whereas the mass number represents the sum of protons and neutrons in the nucleus.

Calculate the number of neutrons by subtracting the atomic number from the mass number.

\text{Number of neutrons} = 23 - 11 = 12

Subtracting the proton count from the total mass number yields the quantity of neutrons.

Key Concept

The number of neutrons in an atom is calculated by subtracting the atomic number (number of protons) from the mass number (total protons and neutrons).

Estimated Time:35s

Question

Answer

Step-by-Step Solution

Key Concept

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