Question

An atom of an element has six electrons in its 3rd orbit which is the outermost shell. Write its

i) electronic configuration ii) valency and iii) number of protons.​

Answer 1

Answer:

Since the outermost shell is 3rd shell its principal quantum no. will be n=3

3rd shell has following subshells : 3s 3p 3d

element has 6 electrons in the 3rd shell so they will be in the above subshells

lets fill the outershell orbitals (brackets represent orbitals and sticks in them represent electrons)

 

   3s  [ l l ]                          s orbital has 2 electrons  

   3p  [ l l ]  [ l  ]  [ l  ]         p orbital has 4 electrons  

   3d  [  ]  [  ]  [  ]  [  ]  [  ]    d orbital is empty              

we have filled the orbitals according to Hund's rule

 i) electronic configuration: 1s2 2s2 2p6 3s2 3p4 3d0 (you can ommit the d                        .                                                               orbital as it is empty)  

 ii) valency: 2 -----> as it can easily gain 2 electrons to achieve a stable                                    .     configuration  

  You can easily guess from the electronic configuration that the element is    .    SULPHUR

  Therefore no. of protons = no. of electrons (for neutral atom)

               iii) no. of protons = 16

I hope it helps ;)