Name the period which is the shortest period and state the number of elements present in it. State the number of elements in the second and the third periods of the periodic table.

Name the elements in the correct order of their increasing atomic numbers present in the first, second and third short periods of the periodic table.
State which of the elements are – (a) metallic (b) non-metallic (c) noble gases in each of the periods 2 and 3.

What are groups in a periodic table. State the property trends in general of elements on moving down in a group of the periodic table. State the characteristics which remain similar on moving down in a group of the periodic table.

Write short notes on the following types of elements –

alkali metals