First slide
Predicting position of element in modern periodic table
Question

An element with Z = 19  belongs to ………….block of modern periodic table

Moderate
Solution

Hints to predict the position of element in the Modern periodic table :

1)Elements from Z = 58-71……Lanthanoids…..4f series….6th period……3rd(IIIB) group;

2)Elements from Z = 90-103……Actinoids…..5f series….7th period……3rd(IIIB) group;

3)Elements from Z = 104-118………..Last two digits gives group number….. 7th period;

4)Elements from Z = 31-57….subtract 18 to get preceding element;

5)Elements from Z = 72-89….subtract 32 to get preceding element;

6)Elements from Z = 104-120….subtract 32 to get preceding element ;

For Z=104-120….simplest Hint

7)Elements from Z = 104-120….subtract 82 to get a lower member(Z<30) belonging to same group;

Hints 4, 5 and 6 can be used repeatedly until an element belonging to same group with Z < 30 is obtained;

Elements with Z < 30 with their group, period and block can be known from Electronic configuration;

Ex : Z=119, 87, 55, 37, 19, 11….belong to 1st(IA) group;

(119-32)=87; (87-32)=55; (55-18)=37; (37-18)=19;(19-8)=11;

Z = 11…..Na….3s1…..n=3….3rd period……s-block….valence electrons(1)….1st group;

Z = 19…..K….4s1…..n=4….4th period……s-block….valence electrons(1)….1st group;

Z = 37…..Rb….5s1…..n=5….5th period……s-block….valence electrons(1)….1st group;

Z = 55…..Cs….6s1…..n=6….6th period……s-block….valence electrons(1)….1st group;

Z = 87…..Fr….7s1…..n=7….7th period……s-block….valence electrons(1)….1st group;

Z = 119…..Uue….8s1…..n=8….8th period……s-block….valence electrons(1)….1st group;

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