Two isotope of chlorine are found in nature, Cl-35 and Cl-37. The average mass or atomic weight of chlorine is 35.45 amu. The most abundant isotope of Cl has [A] 17 protons, 17 electrons, 18 neutrons [B] 17 protons, 17 electrons, 18.45 neutrons [C] 17 protons, 17 electrons, 20 neutrons [D] 18 protons, 18 electrons, 17 neutrons
The correct answer and explanation is :
The correct answer is [A] 17 protons, 17 electrons, 18 neutrons.
Explanation:
To understand this, let’s break down the given information:
- Isotopes of Chlorine (Cl):
Chlorine has two stable isotopes in nature:
- Cl-35: This isotope has a mass number of 35, meaning the sum of its protons and neutrons is 35.
- Cl-37: This isotope has a mass number of 37, meaning the sum of its protons and neutrons is 37.
- Atomic Number and Protons:
The atomic number of chlorine (Cl) is 17, which means every chlorine atom has 17 protons. This is the same for both isotopes. So, Cl-35 and Cl-37 both have 17 protons. - Neutrons:
The number of neutrons in an isotope is determined by subtracting the number of protons from the mass number:
- For Cl-35, the number of neutrons is:
( 35 – 17 = 18 ) neutrons. - For Cl-37, the number of neutrons is:
( 37 – 17 = 20 ) neutrons.
- Electrons:
In a neutral atom, the number of electrons is equal to the number of protons. Since chlorine has 17 protons, it must also have 17 electrons in a neutral state. - Atomic Weight:
The atomic weight or average atomic mass of chlorine is given as 35.45 amu. This value is a weighted average based on the natural abundance of Cl-35 (approximately 75.76%) and Cl-37 (approximately 24.24%). The fact that the atomic weight is slightly above 35 indicates that Cl-35 is the most abundant isotope, with Cl-37 contributing a smaller fraction. - Conclusion:
Since the most abundant isotope is Cl-35, it has 17 protons, 17 electrons, and 18 neutrons.
Thus, the correct answer is [A] 17 protons, 17 electrons, 18 neutrons.
Structure of a chlorine atom with 17 protons, 17 electrons, and 18 neutrons.
Here is the illustration of a chlorine atom (Cl) with 17 protons, 17 electrons, and 18 neutrons, representing the Cl-35 isotope. It shows the structure of the atom with the appropriate number of particles and their arrangement.