Five elements A, B, C, D and E have atomic numbers of 2, 3, 7 10 and 18 respectively.The elements which belong to the same group of the periodic table is :

The Electronic configuration of the atom of an element X is 2,8,4. In modern periodic table, the element X is placed in :

The atomic number of an element is 20. In modern periodic table, this element is placed in :

The elements A, B, C, D and E have atomic numbers 9, 11, 17, 12 and 13 respectively. The pair of elements which belongs to the same group of the periodic table is:

Which of the following element would lose an electron easily?