Name: Shielding Effect and the Effective Nuclear Charge
Uploaded: 2019-07-19
Duration: 13 min 22 s
Description: Do you know how the effective nuclear charge and the nuclear charge differ? How it affects the size of an atom. Watch this video to learn more about it.

Question

Name the group and periods of the elements having atomic number

18, 26, 53

and

82

.

Accepted Answer

The period, group and block of an element can be easily predicted from its electronic configuration as follows:

$(i)$ The period of an element corresponds to the principal quantum number of the valence shell.

$(ii)$ The block of an element corresponds to the type of orbital which receives the last electron.

$(iii)$ The group of an element is predicted from the number of electrons in the valence shell or penultimate shell (last but one, i.e. $n - 1$ ) as follows:

$(a)$ For $s$ -block elements group number is equal to the number is equal to the number of valence electrons.

$(b)$ For $p$ -block elements, group number is equal to $10 +$ number of electrons in the valence shell.

$(c)$ For $d$ -block elements, group number is equal to the number of electrons in $(n - 1)$ $d$ - subshell $+$ number of electrons in valence shell (nth shell)

The electronic configurations of the elements are:

(i) $Z = 18; 1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6}$ (p-block element)

(ii) $Z = 26; 1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{6} 4 s^{2}$ (d-block element)

(iii) $Z = 53; 1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} 4 s^{2} 4 p^{6} 4 d^{10} 5 s^{2} 5 p^{5}$ (p-block element)

(iv) $Z = 82; 1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} 4 s^{2} 4 p^{6} 4 d^{10} 4 f^{14} 5 s^{2} 5 p^{6} 5 d^{10} 6 s^{2} 6 p^{2}$ (p- block element)

Group number for p-block element $= Number of valence electrons + 10$

Group number for d-block element $=Sum of number of electrons in ns and (n-1)d subshell$

For $(i)$ , Group number $= 10 + 8 = 18$ . It belongs to $3^{rd}$ period and group $18$ (zero group). This group is known as noble gas family and this element name is Argon $(Ar)$ .

For $(ii)$ , Group number $= 6 + 2 = 8$ . It belongs to $4^{th}$ period and group $8$ . This group is known as transition elements and this element name is Iron $(Fe)$ .

For $(iii)$ , Group number $= 10 + 7 = 17$ . It belongs to $5^{th}$ period and group $17$ . This group is known as halogen family and this element name is Iodine $(I)$ .

For $(iv)$ , Group number $= 10 + 4 = 14$ . It belongs to $6^{th}$ period and group $14$ . This group is known as carbon family which is present in $p -$ block and this element name is Lead $(Pb)$ .

Name the group and periods of the elements having atomic number $18, 26, 53$ and $82$ .

Important Questions on Periodic Classification of Elements and General Inorganic Chemistry

Learn and Prepare for any exam you want !

Name the group and periods of the elements having atomic number 18, 26, 53 and 82.

Important Questions on Periodic Classification of Elements and General Inorganic Chemistry

Learn and Prepare for any exam you want !

Name the group and periods of the elements having atomic number $18, 26, 53$ and $82$ .