A filament lamp is lit for a short period of time . Touch it . What do you feel ?

Leave the bottle free. What do you observe?

Take 5mL water in a test tube and slowly add concentrated sulphuric acid to it. Touch the bottom of the test tube. What do you feel? Is the reaction exothermic or endothermic?

A piece of magnesium is burned in air. What do you observe ?

A 230 V, 115 W filament lamp works in a circuit for 10 minute . What is the current flowing through the bulb ?

Atomic size, valency, ionization enthalpy, electron gain enthalpy and electronegativity are the important periodic properties of elements. a) What do you mean by periodicity? b) Periodic properties are directly related to ͟ ͟ ͟͟͟