Write the electronic configuration of the elements given below and also predict the block, group number and period to which they belong. (`Z=` Atomic number)
I. `A(Z=5)`, `B(Z=11)`, `c(Z=28)`,
`D(Z=54)`, `E(Z=59)`, `F(Z=90)`.

Explanation

I. Element A `(Z =5)`: Name of element `=` Boron , (B) Electronic conjuration of `A = 1s^(2) 2s^(2) 2p^(1)`
The last electron enters in `2p` orbital, therefore it belongs to p-block elements
Group number `= 10+` Number of electrons in the valence shell
`= 10 +3 = 13`
Period of the element `=` Number of the principal quantum number of the valence shell `= 1`
Period of the element `=` Number of the principal quantum number of shell `= 3rd`
Element `C(Z =28)`: (Name of element = Nickel) `(Ni)` Electronic configuration of C : `1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 3d^(8) 4s^(2)`.
The last electron enters into `3d`-orbital, therefore it belongs to d-block elements.
Group Number `=` Number of electrons in the penultimate shell `+` number of electrons in the valence shell `= 8+2=10`.
Period of the element: Number of principal quantum number of the valence shell `= 4th`.
Element `D (Z = 54)`: of D Name of element = Xenon `(Xe)` Electronic configuration: `1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 3d^(10) 4s^(2) 4p^(6) 4d^(10) 5s^(2) 5p^(6)`
The last electron is present is `5p`-orbital, therefore it belongs to the p-block elements.
Group number `= 10+` Number of electrons in the valence shell `= 10+8 18`.
Period of the element `=` Number of principal quantum number of the valence shell `= 5th`.
Element `E(Z = 59)`: Name of element `=` Praseodymium `(Pr)`
Electronic configuration of E: `1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 3d^(10) 4s^(2) 4s^(6) 4d^(10) 5s^(2) 5p^(6) 6s^(2) 5d^(1) 4f^(2)`.
? But its actual electronic configuration is `6s^(2), 4f^(3)`.
The last electron enters into the `4f`-orbital, therefore it belongs to f-block elements.
Group Number : Since it belongs to the lanthanide series, therefore as such it does not have any group number of its own but it is considered to lie in group 3.
Period of elements: Number of principal quantum number of the valence shell `= 6th`.
Element `F(Z = 90)` : Name of the element `=` Thorium `(Th)`
Electronic configuration of F: `[Rn] 6d^(1) 75^(2) 5f^(1)` But its actual electronic configuration is `[Rn] 6d^(2)7s^(2)`.
The last electron enters into the `5f`-orbital, therefore it belongs to f-block elements.
Group number: Since it belongs to actinide series, therefore as such it does not have any group number of its own but it is considered to lie in group 3.
Period of the elements `=` Number of principal quantum number of the valence shell `= 7th`.
II. Elements A and B are representative elements since their last electron enters in s- and p- orbitals respectively.
Element C is a transition element since its last electron enters in the d-orbital.
Elements D is a p-block element with completely filled s-and p-prbitals of the valence shell and is called a noble gas.
Elements E and F are an inner transition elements since their last electron enters in the f-orbital.