If x = Group number of Europium (atomic number 63)

y = Period number of Americium (atomic number 95)

z = Most stable oxidation state shown by Gadolinium (atomic number 64)

s – block and p – block elements together are called as representative elements.

Zn (Z = 30) is a d-block element.

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You can read the classification of elements and periodicity in properties class 11 notes to study class 11 ch3 and score well in class 11th exams and NEET, and JEE exams.

When the elements having similar properties repeat at regular intervals, it is called periodicity in the properties of elements.

Classification of Elements is Necessary because it helps in understanding and remembering elements' properties better, you can understand how elements react or behave, and can guess properties of unidentified or newly discovered elements.