Show that the circumference of the Bohr orbit for the hydrogen atom is an integral multiple of the de Broglie wavelength associated with the electron revolving around the orbit.

5

(a)

Calculate the energy required for the process
\(He^{ + }\left( g \right) \longrightarrow { He }^{ 2+ }\left( g \right) +{ e }^{ - }\) 
The ionization energy for the H atom in the ground state is 2.18 × 10^–18 J atom^–1

5

(a)

A beam of helium of atoms move with a velocity of \(2.0\times { 10 }^{ 3 }{ ms }^{ -1 }\) Find the wavelength of the particle constituting the beam. (h = 6.626 \(\times \)10^-34 Js).

5

(a)

List the quantum number (m_l and l) of electrons for 3d - orbital.
Notes:
l has the value 0 to (n - 1)
m has the value -l to l
The value of l never be equal to n or greater than it.

5

(a)

An electron is moving with a kinetic energy of \(2.275\times { 10 }^{ -25 }J\) 
Calculate its de-Broglie wavelength. ( Mass of electron =  \(9.1\times { 10 }^{ -31 }kg\), \(h=6.6\times { 10 }^{ -34 }Js\))

5

(a)

What are the atomic numbers of elements whose outermost electrons are represented by
a) 3s²
b) 2p³
c) 3p⁵ ?

5

(a)

(a) What is the limitations of Rutherford model of atoms?
(b) How has Bohr's theory helped in calculating the energy of hydrogen electron in different energy levels?

5

(a)

Define atomic number, mass number and neutron. How are the three related to each other?

5

(a)