Rebecca H.

-There are 3 types of bonds: ionic, covalent, and metallic bonds.

Characteristics of Ionic Bonds

• Have High melting points
• Have Conduct electricity
• Dissolve easily in water
• Have well-defined crystals
• Soluble in H2O.
• Insoluble in nonpolar solvents.

Examples: NaCl, CaCO3

Ionic bonding is the process of formation of a chemical bond by complete transfer of electrons from one atom to another. When the atoms lose or gain electrons, they become differentially charged ions or oppositely charged ions. The charged ions are then attracted towards each other due to the resulting electrostatic force. The electrostatic force gives rise to the formation of an ionic bond. A negative ion (Anion) and a positive ion (Cation) are formed during the chemical ionic bonding.

The most common example of ionic bonding is the formation of sodium chloride in which the sodium atom donates its outer electron to the chlorine atom, which required only one electron to fill its outer shell. The sodium ion becomes positively charged due to the loss of electron whereas the chloride ion becomes negatively charged due to the addition of the electron. The oppositely charged ions therefore are attracted to each other and result in the formation of an ionic bond.

Also ionic bonding commonly occurs in metal salts such as sodium chloride (table salt).

Ionic bonds occur between metals and nonmetals when there is a large difference in electro negativity.

Some facts about the strong ionic bonds…
Much of the strength of ionic bonding comes about when
the ions are packed together in crystal lattices, so that
each ion is held in an attractive field with several neighbors
of the opposite charge. These binding energies
can range up to several thousand kilojoules per mole.

Characteristics of Covalent Bonds

• covalent bonds are molecules (neutral)
• do not conduct electricity
• low melting and boiling points
• bond strength is high but lesser than ionic bond
• they are not soluble in water
• Soluble in nonpolar solvents.
• Nonlustrous

Some Examples: Hydrogen, Carbon, Nitrogen, and Oxygen all form covalent bonds

When a sharing of valence electrons happens between atoms, a covalent bond is formed. A polar covalent bond is formed when two atoms do not share the valence electrons equally.

In covalent bonds the atoms share the electrons. Let's take the example of water. A single water molecule is H2O. It consists of two hydrogen atoms and a single oxygen atom. A water molecule is formed when an oxygen atom and a hydrogen atom donate one electron to form a chemical bond. This type of bonding is known as single covalent bond.

In a double covalent bond two valence electrons are shared. For instance, oxygen in air does not exist as a single atom. The two oxygen atoms share 2 valence electrons each to form O2.

Examples for each plus triple covalent bond:
Single covalent bond – 2 atoms share exactly one pair of electrons.

Examples: H2, F2, I2 and other diatomic molecules are molecules that contain single covalent bonds.

Double covalent bond- consists of two pairs of shared electrons.

Examples: O2, CO2 and H2CO (formaldehyde) are molecules that contain double bond.

Triple covalent bonds- consist of three pairs of shared electrons.

Examples: C2H2 (ethyne) and N2 are molecules that contain triple bonds.

So In Covalent Bonding the valence electrons are shared as pairs between the bonded atoms. Pure covalent bonding only occurs when two nonmetal atoms of the same kind bind to each other. When two different nonmetal atoms are bonded or a nonmetal and a metal are bonded, then the bond is a mixture of covalent and ionic bonding called polar covalent bonding.

Characteristics of Metallic Bonds

• Malleable solid
• High melting point and boiling point
• Insoluble in H2O
• Insoluble in nonpolar solvents
• Conducts heat and electricity
• Lustrous

Examples: gold & copper


In Metallic Bonding the valence electrons are shared among all of the atoms of the substance. Metallic bonding occurs when metals bond to either themselves or mixed with other metals in alloys.