Question

find the group or period of Helium.?

Answer 1

hi dear.
Helium is placed in First period and 18th or zero group in Modern periodic table.
It is an INERT gas and its symbol is He.
I hope you get the ans.
THANK YOU.

Answer 2

Hi !

Helium :-

Atomic no: = 2
No of protons = 2
No: of electrons = 2
Electronic configuration = 2

The period no: of an element can be found out be looking  at the no: of shells.

As helium has only one shell , it belongs to the period 1 .

Also , as helium in a noble gas(inert) , it is of the group 18.
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Taking another example , to find the group no: , where the element is not inert.

Oxygen :-

Atomic no: = 8
No: of electrons = 8
Electronic configuration = 2,6

Here , group no: can be found out by adding 10 to  the no: of valence electrons.

here , valence electrons = 6

Hence, group no: = 10 + 6 = 16

group no : of oxygen = 16