Structure of At...

An element has three electrons in the 4th shell, the atomic number of the element is:

$$12\ g$$ of a trivalent element combines with $$4\ g$$ of oxygen. Its atomic mass is:

Radius of $$2nd$$ shell of $$He^+$$ (where $$a_0$$- Bohr radius)

The number of orbitals in n = 3 are:

The active mass of $$7.0\ g$$ of nitrogen in a $$2.0\ L$$ container would be:

The key feature Of Bohr's theory Of spectrum Of hydrogen atom is the quantization Of angular momentum when an electron is revolving around a proton. We will extend this to a general rotational motion to find quantized rotational energy Of a diatomic molecule assuming it to be rigid. The rule to be applied is Bohr's quantization condition.A diatomic molecule has moment Of inertia I. By Bohr's quantization condition its rotational energy in the nth level (n=0 is not allowed) is 

The electronic configuration of an element is $$1s^2, 2s^2, 2p^6, 3s^23p^3$$. What is the atomic number of the element which is just below the given element in the periodic table?

$$7.8$$ grams of metal in water and liberated $$2.24L$$ of hydrogen at standard conditions. Calculate the atomic number of the metal.

If an electron jumps from orbit $$A$$ to orbit $$B$$ it loses energy while when it jumps from $$C$$ to $$B$$ it gains energy. Arrange the orbits in the increasing order of distance from the nucleus.

The orbit having Bohr radius equal to $$1^{st}$$ Bohr orbit of $$H-$$atom is: