Which of the following is the atomic number of an atom that has 12 protons and 12 neutrons?
A.
24
B.
12
C.
1
D.
144
The correct answer and Explanation is :
The correct answer is B. 12.
Explanation:
The atomic number of an atom is defined as the number of protons present in its nucleus. It determines the element to which the atom belongs and also influences its position in the periodic table.
In this case, the atom in question has 12 protons. Therefore, its atomic number is 12. The number of neutrons does not affect the atomic number; it affects the atom’s mass number, which is the total number of protons and neutrons in the nucleus.
To elaborate, the atomic number is fundamental in defining the identity of an atom. For example, an atom with 12 protons is identified as magnesium (Mg) on the periodic table. The atomic number of an element determines its chemical properties and its place in the periodic table.
The mass number of an atom is calculated by adding the number of protons and neutrons. For this atom, with 12 protons and 12 neutrons, the mass number would be (12 + 12 = 24). This mass number is not the same as the atomic number; it is used to determine the isotope of the element.
In summary:
- Atomic number = number of protons
- Mass number = number of protons + number of neutrons
For this specific atom:
- Atomic number = 12 (corresponding to magnesium)
- Mass number = 24 (indicating it is the isotope magnesium-24)
The options given in the question are:
A. 24
B. 12
C. 1
D. 144
The correct option based on the atomic number is B. 12.