Atoms combine as the electrons from each atom are attracted to the nuclei of the atoms. This results in bonds ranging from 100% covalent to bonds with high ionic character. The combination of atoms to form compounds occurs when the compounds being formed are at lower energy than the original atoms
Solid lead nitrate in water gives lead oxide and nitric acid
Pb(NO3)2 + H2O ---> PbO + 2 HNO3
Explanation:
A mixture is made of two or more substances that are not chemically combined whereas a compound is made of 2 or more elements that are chemically combined. The elements that make up the compound are combined in fixed ratios.
Magnesium dichloride or Magnesium chloride
C is correct. Have a good day!