Question

Which element has 1s2s2p3s3p electron configuration?

Answer 1

Answer:

                  The Element can either be,

                                 i) Aluminium (Al)

                                 ii) Silicon (Si)

                                 iii) Phosphorous (P)

                                 iv)  Sulfur (S)

                                 v) Chlorine (Cl)

Or,

                                 vi) Argon (Ar)

Explanation:

                            The best and easiest way to identify major group (s and p block) elements using periodic table is by studying their electronic configuration.

Identifying Group of an Element:

                                                      The group of an element can be identified by counting the number of valence electrons present in the valence shell of an atom.

Examples:

i)  Sodium:  

            Electronic configuration of Sodium is as follow,

                                                     1s², 2s², 2p⁶, 3s¹

As there is only one valence electron in valence shell of sodium (3rd shell) hence, it is present in group 1 of the periodic table.

ii)  Neon:  

            Electronic configuration of Neon is as follow,

                                                       1s², 2s², 2p⁶

As there are eight valence electrons in valence shell of neon (2nd shell) hence, it is present in group 8 of the periodic table.

Identifying Period of an Element:

                                                      The number of period in which the element is present is equal to the valence shell number of that element.

Examples:

i) Sodium:

            Electronic configuration of Sodium is as follow,

                                                     1s², 2s², 2p⁶, 3s¹

As the valence shell is 3, therefore, Sodium is present in 3rd Period.

ii) Neon:

            Electronic configuration of Neon is as follow,

                                                     1s², 2s², 2p⁶

As the valence shell is 2, therefore, Neon is present in 2nd Period.

Conclusion:

                  As in statement we are not given with the number of electrons present in the shells and sub-shells of the electronic configuration hence, we can conclude that this electronic configuration can belong to either;

Aluminium, as it has electronic configuration 1s², 2s², 2p⁶, 3s², 3p¹.

Silicon, as it has electronic configuration 1s², 2s², 2p⁶, 3s², 3p².

Phosphorous, as it has electronic configuration 1s², 2s², 2p⁶, 3s², 3p³.

Sulfur, as it has electronic configuration 1s², 2s², 2p⁶, 3s², 3p⁴.

Chlorine, as it has electronic configuration 1s², 2s², 2p⁶, 3s², 3p⁵.

Argon, as it has electronic configuration 1s², 2s², 2p⁶, 3s², 3p⁶.

As the valence shell is same and extended up to p sub-shell hence this electronic configuration is for any atom present in period 3 and p block respectively.

Answer 2

To answer this problem, we need to count the electrons in the given configuration. The complete configuration is 1s2 2s2 2p6 3s2 3p6. There are 2+2+6+2+6 equal to 18 electrons. We find next the element with an atomic number of 18. That element is noble gas argon.