2. Write down the position of alkaline earth metal in the Modern periodic table What is their valency?

they are in group II and they have two electrons in their outermost energy levels ( valency)...is this helpful?

Group II (Second left group)

Valency = 2

More Information :

The alkaline earth metals are named after their oxides, the alkaline earths, whose old-fashioned names were beryllia, magnesia, lime, strontia, and baryta. These oxides are basic (alkaline) when combined with water.

The elements are

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.

a electronegativity decreases beacuse the size of nucleus is bigger.