Covalent Bonding

Covalent bonding occurs when the atoms making the compound shares electrons to achieve a stable configuration.

Usually non-metals and non-metals make covalent bonds. for example hydrogen atom has only one electron in the outer shell. when it shares this one electron with another hydrogen atom both the hydrogen atoms can achieve the noble gas configuration.

However compounds made by covalent bonding is not strong as the ionic bond. Therefore these compounds will have lesser boiling points and melting points. they will not be readily soluble in water and the aqueous solutions will not conduct electricity because no ions will be present to conduct electricity .

Covalent bonding in Hydrogen

Ionic Bonding

Ionic bond is a bond between a metal and a non metal. Metals are elements with shiny surfaces, sonorous sounds, malleable and with good conductors of heat and electricity.

Metals usually have upto 3 electrons in their outer most shell (in non transitional elements). To achieve the noble gas configuration they would release these electrons and become positive ions.
Non metals in the other hand (mainly group V,VI,VII elements in the periodic table) has 5, 6 or 7 electrons in their outermost shell. In order to achieve a stable electronic configuration these elements can accept electrons and become negative ions. Electrostatic attraction between a positive ion and a negative ion makes ionic bonding.

compounds with ionic bonds are having properties such as high melting points, boiling pointsand readily soluable in water .

Next about covalent bonding