The molecules vibrate when the substance is heated, and the shape of the substance begins to form a different shape. For example: when you hear up metal it will melt becuase its molecules are changing and moving.
It states the fact, which we now know, that electrons are responsible for the chemical bonding. According to this theory, valency is the number of electrons present in the outermost energy shell of the atom. This energy shell is called valency shell.
A.) Phosphate ion or Orthophosphate
d.) Hydroxide
D.) Ammonium
e.) Iron
C.) Nitrate
f.) Sulfur dioxide