Chemical Bond: is the force that holds atoms together in a compound. They form because they lower the potential energy of the charged particles that compose atoms. Chemical bonds can be broadly classified into two types: Ionic and Covalent.
Ionic: metal & nonmetal
Metals have a tendency to lose electrons and nonmetals have a tendency to gain them. The metal atom becomes a cation and a nonmetal becomes an anion. The oppositely charged ions attract one another and form an ionic compound
Covalent: nonmetal & nonmetal
Covalent bonds are shared; Ionic bonds are distributed
Covalent bonds are stronger than Ionic bonds
Ionic Compounds: Ionic compounds consist of positive and negative ions. The ions are held together by strong attractions between the oppositely charged ions, called ionic bonds
Properties of ionic Compounds:
The physical and chemical properties of an ionic compound such as NaCl are very different from those of the original elements. For example, the original elements of sodium chloride were Sodium, which is a soft, shiny metal, and chlorine, which is a yellow, green, poisonous gas. When they combine, they form salt
Formulas
Formulas of Ionic Compounds: The chemical formula of a compound represents the symbol and subscripts in the lowest whole number ratio of the atoms or ions. In the formula of an ionic compound, the sum of the ionic charges is always zero, which means that the total amount of positive change in equal to the total amount of negative charge.
CaCl2
Subscripts in Formulas: A compound of magnesium and chlorine. To achieve an octet, a magnesium atom loses its two valence electrons to form Mg2+. Two Chlorine atoms each gain one electron from two Cl- ions. The two ions are needed to balance the positive charge of Mg2+. This gives the formula, MgCl2
Writing ionic formulas from ionic charges
The subscripts in the formula of an ionic compound represent the number of positive and negative ions that give an