Ratio of Atomic Radius of 5th Orbit in Chlorine Atom to 3rd Orbit in Helium Atom

The atomic radius of an atom is defined as the distance between the nucleus and the outermost shell of electrons. The atomic radius depends on the number of electron shells and the effective nuclear charge experienced by the outermost electrons.

Chlorine Atom
- Chlorine (Cl) is a halogen and has an atomic number of 17.
- The electron configuration of chlorine is 2, 8, 7, indicating that it has three electron shells.
- The 5th orbit refers to the outermost shell in chlorine, which contains 7 electrons.

Helium Atom
- Helium (He) is a noble gas and has an atomic number of 2.
- The electron configuration of helium is 2, indicating that it has two electron shells.
- The 3rd orbit in helium refers to the outermost shell, which contains 2 electrons.

Ratio Calculation
To calculate the ratio of the atomic radius, we need to consider the number of electron shells in each atom.

- The atomic radius is directly proportional to the number of electron shells.
- Chlorine has 3 electron shells (5th orbit is the outermost), and helium has 2 electron shells (3rd orbit is the outermost).

Ratio Calculation:
Atomic radius ratio = Number of electron shells in chlorine / Number of electron shells in helium
= 3/2
= 1.5

This ratio indicates that the atomic radius of the 5th orbit in chlorine is 1.5 times larger than the atomic radius of the 3rd orbit in helium.

Conversion to Simplified Ratio:
To simplify the ratio, we multiply both sides by a common factor to obtain whole numbers.
- In this case, multiplying both sides by 100 gives:
Atomic radius ratio = 1.5 * 100/1 * 100
= 150/100
= 3/2

Thus, the simplified ratio of the atomic radius of the 5th orbit in chlorine to the 3rd orbit in helium is 3:2.

Final Answer:
Option B) 50:153 is the correct ratio of the atomic radius of the 5th orbit in chlorine to the 3rd orbit in helium.