An atom has 14 protons and 20 neutrons. What is its atomic number?
A.
20
B.
17
C.
10
D.
14
The correct answer and Explanation is :
The correct answer is D. 14.
Here’s an explanation:
To determine the atomic number of an atom, we need to understand what the atomic number represents. The atomic number is defined as the number of protons in the nucleus of an atom. It is a fundamental characteristic that defines the identity of an element. Each element in the periodic table has a unique atomic number, which corresponds to the number of protons in its nucleus.
In this problem, the atom is described as having 14 protons. By definition, the atomic number is the number of protons in an atom. Therefore, for this atom, the atomic number is 14.
The number of neutrons in the atom does not affect the atomic number. Instead, the number of neutrons, combined with the number of protons, helps determine the atomic mass of the atom. The atomic mass number is calculated by adding the number of protons and neutrons together. In this case, the atomic mass number of the atom would be:
[ \text{Atomic Mass Number} = \text{Number of Protons} + \text{Number of Neutrons} ]
[ \text{Atomic Mass Number} = 14 + 20 = 34 ]
However, the atomic number remains solely determined by the number of protons. Hence, regardless of the number of neutrons, the atomic number is still 14.
For example, the element with atomic number 14 is silicon (Si) on the periodic table. Each element is uniquely identified by its atomic number, and this number is crucial for understanding the element’s position and behavior in the periodic table.