Question

An element ‘X’ (Atomic number = 20) burns in the presence of oxygen to form a basic oxide. (a) Identify the element and write its electronic configuration. (b) State its group number and period number in the Modern Periodic Table. c) Write a balanced chemical equation for the reaction when this oxide is dissolved in water.

Answer 1

a) Element is Calcium. It belongs to the 2nd group and 3rd period of the Modern Periodic table.

Answer 2

a) calcium is the element having electronic configuration is 2, 8 ,8,2
b) belongs to the second group and third Period of the modern periodic table
c) CaO + H2O --------> CaO(OH)2