Question

According to Bohr's model, the radius of the seconds orbit of helium atom is:

• A. $0.53\mathring{A}$
• B. $1.06\mathring{A}$
• C. $2.12\mathring{A}$
• D. $0.265\mathring{A}$

Answer 1

The correct option is B $1.06\mathring{A}$

According to Bohr' model,

$r_n=0.529\times \frac{n^2}{Z}$

where,

$0.529\mathring{A}=$ radius of first orbit of hydrogen atom

We have to find that radius of the seconds orbit of helium atom,

$n=2$

$Z=2$

$\therefore r_2=0.529\times \frac{2^2}{2}=1.058=1.06\mathring{A}$

Hence, according to Bohr's model, the radius of the seconds orbit of helium atom is $1.06\mathring{A}$.