Check sibling questions

Three elements ‘X’, ‘Y’ and ‘Z’ have atomic numbers 7, 8 and 9 respectively.

 

Answer

(a)

X

Y

Z

Atomic number of X = 7

Electronic configuration: 2, 5

Group number = 10 + number of electrons in outermost shell=10 + 5 = 15

Since there are 2 shells, Period = 2nd

X is nitrogen

Atomic number of Y = 8

Electronic configuration: 2, 6

Group number = 10 + number of electrons in outermost shell=10 + 6 = 16

Since there are 2 shells, Period=2nd

Y is oxygen

Atomic number of Z = 9

Electronic configuration: 2, 7

Group number = 10 + number of electrons in outermost shell=10 + 7 = 17

Since there are 2 shells, Period=2nd

Z is Fluorine

(b)

Modern Periodic table-01 - Teachoo.jpg

As we move across a period from left to right, atomic radii decreases. X, Y and Z belong to the same period ie., 2 and in the modern periodic table, X comes to the left of Y and Z comes to the right of Y . So the atomic radius of X is more than Y and the atomic radius of Z is less than Y. 

So,the order of their atomic radii is: X>Y>Z

(c)

Valency of X = 8 - 5 = 3

Valency of Z = 8 - 7 = 1

Reaction of X with Z - Teachoo.jpg

X reacts with Z to form XZ 3

 

 

 

 

 


Transcript

Reaction of X with Z Valency

CA Maninder Singh's photo - Co-founder, Teachoo

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CA Maninder Singh

CA Maninder Singh is a Chartered Accountant for the past 12 years and a teacher from the past 16 years. He teaches Science, Economics, Accounting and English at Teachoo