Question

using bohar atomic model dries expression for calculating the radius of orbit in hell I'm using the expression calculate the radius of fourth orbit of helium ion

Answer 1

According to Bohr's model of an atom,
The radius of an atom =
$\frac{ {n}^{2} \times 5.3 \times {10}^{ - 11} m}{z}$

where, n is the number of orbit and z is the atomic number.
Atomic number of Helium = 2
Orbit no. = 4
Therefore, radius =
$\frac{ {4}^{2} \times 5.3 \times {10}^{ - 11} }{2}$

$= \frac{8 \times 5.3 \times {10}^{ - 11} }{2}$

$= 2.12 \times {10}^{ - 10} m$