What is ratio of t1 t2 in second orbit of hydrogen atom to third orbit of He+ ion?

India's Super Teachers for all govt. exams Under One Roof

Enroll For Free Now

CONCEPT:

Bohr's Atomic Model:

Bohr proposed a model for hydrogen atom which is also applicable for some lighter atoms in which a single electron revolves around a stationary nucleus of positive charge Ze (called hydrogen-like atom).

Bohr's model is based on the following postulates:

He postulated that an electron in an atom can move around the nucleus in certain circular stable orbits without emitting radiations.
Bohr found that the magnitude of the electron's angular momentum is quantized i.e.

\(⇒ L = m{v_n}\;{r_n} = n\left( {\frac{h}{{2\pi }}} \right)\)

Where n = 1, 2, 3, ..... each value of n corresponds to a permitted value of the orbit radius, rn = Radius of nth orbit, vn = corresponding speed, and h = Planck's constant

EXPLANATION:

According to Bohr's atomic model, the speed of the electron in the nth orbit is given as,

\(⇒ v_n=2.2\times10^6\frac{Z}{n}\,m/sec\) -----(1)

Where Z = atomic number

For ground-state n = 1,

\(⇒ v_n=2.2\times10^6\times\frac{Z}{1}\,m/sec\)

⇒ vn ∝ Z -----(2)

For H atom, Z = 1

For He+ ion, Z = 2

For Li+2 ion, Z = 3

By equation 2 we can say that the speed of the electron in the ground state is directly proportional to the atomic number.
We know that the atomic number of Li+2 is maximum compared to the H atom and He+ ion.
So the speed of the electron in the ground state is maximum for Li+2 ion. Hence, option 3 is correct.

India’s #1 Learning Platform

Start Complete Exam Preparation

Daily Live MasterClasses

Practice Question Bank

Mock Tests & Quizzes

Get Started for Free Download App

Trusted by 3.4 Crore+ Students

NEET neet - Chemistry

Solve this plz !

Asked by jhajuhi19 | 16 Jul, 2021, 08:42: AM

ANSWERED BY EXPERT

NEET neet - Chemistry