Metallic And Non Metallic Character

Metallic And Non Metallic Character

Metals:

The metals are characterised by their nature of readily giving up the electrons.

• Metals comprise of more than 75% of all known elements and most of them appear on the left hand side of the periodic table.
• Metals are usually solid at room temperature (except Mercury).
• They have high melting and boiling points and are good conductors of heat and electricity.

Non–Metals:

• Non-metals do not lose electrons but take up electrons to form corresponding anions.
• Non-metals are located at the top right hand side of the periodic table.
• Non-metals are usually solids or gases (except Bromine which is liquid) at room temperature with low melting and boiling points.
• They are poor conductors of heat and electricity.

Metalloids (Semimetals):

• Some elements lying at the border of metallic and non-metallic behaviour possess the properties that are characteristics of both metals and non - metals. These elements are called semimetals or metalloids.
• The metalloids comprise of the elements B, Si, Ge, As, Sb, Te and Po.
• Variation of metallic character across a period: Metallic character decreases along a period due to increase in ionisation energy.
• Variation of metallic character along a group: Metallic character increases on going down a group from top to bottom. This can be explained in terms of decrease in ionisation energy on going down a group from top to bottom.

NOTE : Metals generally form cations by losing electrons from their outermost shell, while non- metals generally form anions by accepting one or more electrons.

e.g. Alkali metals form M+ ions by losing one electron, while alkaline earth metals form M–1 ions by losing two electrons from their outermost shell.