Atoms, Molecules, Ions, Bonds

Hamza Huq

Ionic Bonds

They form between two atoms when one or more electrons are transferred from one atom to the other.

Ex.Sodium (Na+) and Clhrorine (Cl-) ions bond and form a molecule of sodium chloride (NaCl)

Covalent Bonds

They form when electrons between atoms are shared, Which means that neither atom completely retains possession of the electrons (as happens with atoms that form strong ionic bonds).


  • Nonpolar covalent bonds form when electrons between atoms are shared equally. Ex. Two identical atoms sharing electrons such as oxygen gas (O_2)
  • Polar covalent bonds form when electrons between atoms are unequally. Ex. Water (H20) and electrons are shaered between the oxygen atom and each hydrogen atom
  • Single colvalent, double covalent, and triple covalent bonds form when two, four, and six electrons are shared, respectively.

Hydrogen Bond

They form weak bonds between molecules. Ex.In water, the positive pole around a hydrogen atom forms a hydrogen bond to the negative pole around the oxygen atom of another molecule.

Properties if Water

Solvent

Water is an excellent Solvent. Thing that can dissolve easily.

Heat Capacity

Water has a high heat capacity. When a substance can gain or lose heat.

Cohesion and high surface tension

The Attraction between like substances, occur in water because of the hydrogen bonding between water molecules.

The strong cohesion between water molecules produces a high surface tension creating a firm water surface.

Adhesion and Capillary action

The attraction of unlike substances

By rising up the tubing or creeping through the paper