Questions

Covalent bonding occurs when pairs of electrons are shared by atoms. Atoms will covalently bond with other atoms in order to gain more stability, which is gained by forming a full electron shell. By sharing their outer most (valence) electrons, atoms can fill up their outer electron shell and gain stability.

Examples of compounds with covalent bonds ::

HCl, CO2, O2,... 

Atoms of the same element can have same atomic number and number of electrons since, the atomic number is the number of protons and the number of protons and eectrons are the same in an element.

Hence, the atoms of the same element may differ in their atomic mass since it depends on the number of neutrons it holds and such atoms are called isotopes.

Androgens such as testosterone are produced by the Interstitial cells.

Most medieval music was instrumental.

Shivaji Maharaj was the founder of Maratha empire.