Introduction

• All chemical and physical properties are seen due to the electronic configuration of elements. • The ionization enthalpy of the extreme left element in a period is the least. • The electron gain enthalpy of the element on the extreme right is the highest negative. • This results into high chemical reactivity at the two extremes and the lowest in the centre. The metallic character of an element, which is highest at the extreme left decreases and the non-metallic character increases while moving from left to right across the period. • The chemical reactivity of an element can be best shown by its reactions with oxygen.

Pre-Requisites:

Element, valence shell, electron gain enthalpy, ionization energy, electronic configuration

Activity:

Rust – formation of iron oxide on the surface of metals such as iron.

Real Life Question:

How does rust form on iron?

Key Words / FlashCards

Learning aids / Gadgets

Real life uses :

To avoid rust formation, objects made of iron are painted to cut the contact with air containing oxygen.

Places to visit :

Garage, roof

Practical examples around us

What you learn in Theory:

Chemical Reactivity is at the two extremes of the periodic table (ignore noble gases) and the lowest in the centre.

What you learn in Practice:

Metals in the 1 and 2 group and non metals in the halogen groups are highly reactive.