Structure of At...

Potassium selenate is isomorphous with the potassium sulphate and contains 50.0% of $$Se$$. Find the atomic weight of $$Se$$.

The radius of first excited state of $${ Be }^{ 3+ }$$ ion is:

The e/m of proton is

The moment of momentum of electrons in the third orbit in a hydrogen atom 

The radius of the hydrogen atom in the ground state is $$0.53 {\mathring A}$$, the radius of $$L{i^{2 + }}$$ in a similar state is____.

Ionization energy of $${He}^{+}$$ is $$19.6\times {10}^{-18}J{atom}^{-1}$$. The energy of the first stationary state ($$n=1$$) of $${Li}^{2+}$$ is

Which among the following elements does not contain same number of s-electrons as the number of d-electrons in $${ Ni }^{ 2+ }$$? (Atomic number of Kr is 36) 

Name the compounds used in preparation of nylon-66.

The radius of the first Bohr orbit of a hydrogen atom is $$ 0.53\times 10^{-10}m$$.When an electron collides with this atom which is in its normal state, the radius of the electron orbit in the atom change to $$2.12 \times 10^{10}m$$.The value of the principal quantum number $$n$$ of the state to which it is excited is:

If transition of an electron in $$H-atom$$ takes place from $$3rd$$ orbit to $$5th$$ then change in angular momentum of electron is given by?