Question

which of the alum which of the element have the electronic configuration 1S2 to and 2S4​

Answer 1

Explanation:

A number of electrons present in valence shell of penultimate Shell represents the group of elements.

For s block elements: no.of group=number of valence shell electron.

p block elements: no. of group= 2 + 10 + number of valence electrons.

d block elements: no. of group= number(n-1)d electrons + number of electrons in nth shell.

Here, the differential electron is in p orbital hence, it belongs to p block

No.  of group= 2+ 10 + 3=15 i.e 15th group or VA group

The electron configuration of an atom shows the number of electrons in each sublevel in each energy level of the ground state atom.

Here, 1s

2

2s

2

2p

6

3s

2

3p

2

3d

5

4s

1

 is ground state electronic configuration of Cr.

Note: To write the electronic configuration a more convenient way is