Find out the number of waves made by a Bohr electron in once complete revolution in its 3rd orbit?

The two types of bond present in B₂H₆ are covalent and _______.

Using the VSEPR theory, identify the type of hybridization and draw the structure of OF₂. What are the oxidation states of O and F?

A 4 : 1 molar mixture of He and CH₄ is contained in a vessel at 20 bar pressure. Due to a hole in the vessel the gas mixture leaks out. What is the composition of the mixture effusing out initially?