Question

Explain why the first period of the periodic table is exception
in case of
a) Each period starts with altali metal and ends with nobel gases .​

Answer 1

Answer:

It is an exception because even though it ends with a noble gas (helium) the position of the first element i.e. hydrogen is uncertain. This is because hydrogen shows the characteristics of both alkali metals (group 1) and halogens (group 17)

Answer 2

Explanation:

1. it is an exception because even though it ends with a noble gas helium the position of the first element that is hydrogen is uncertain.
2. this is because hydrogen shows the characteristics of both alkali metals group 1 and halogens group17.