Question

Three elements 'X', 'Y' and 'Z' have atomic numbers 7, 8 and 9
have atomic numbers 7, 8 and 9 respectively.
(a) State their positions (Group number and period num
ons (Group number and period number both) in the Modern Periodic Table.
(b) Arrange these elements in the decreasing order of their atomic radil.
(c) Write the formula of the compound formed when
mula of the compound formed when 'X' combines with Z​

Answer 1

Explanation:

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closed The atomic numbers of three elements X,Y and Z are 9, 11 , 17 respectively . which of the two elements show similar characteristicts and why ?

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asked Dec 23, 2015 in Class X Science by luckky ramya Expert (1.8k points)

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answered Dec 23, 2015 by maaz Expert (2.2k points)

Look this is HOW WE DO

Electronic Configuration of X : - 2,1,6

Electronic Configuration of Y : - 2,8,1

Electronic Configuration of Z : - 2,8, 7

Elements X and Y have similar chemical properties.

Reson : - They have same number of electron in outermost shell. Their valency is same (1)

Answer 2

Here is your answer with explanation :

element x has atomic no 7

therefore electronic configuration is 2,5

group no =10 +5=15 and period no = 2(no of shells)

element y has atomic no 8

electronic configuration  is 2, 6

group no = 16 and period no = 2

element z has atomic no 9

electronic configuration is 2,7

group no =17 and period no =2

atomic radii in decreasing order is

a) z

b)y

c)x

(atomic radii decreases from left to  right in the modern periodic table)

formula of compound when x combines with z =

      xz