Question

anyone know please metion the reason too in simple language...
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Answer 1

Answer: (2) K

Explanation: Its easy to understand

Note that all the options except (2) are the elements of 3rd period.

And (2) is the element of 4th period.

So, just select the odd one out .

Please mark my answer as brainliest if you think it is perfect.  

Thank you !!!

Answer 2

Answer:

ca and magnesium salts are responsible for hardness of water.

if size of Ca(metal x) is larger than Mg(metal y) that means Ca is before Mg in the period as size decreases in a period from left to right.

now Mg is in third period so K ie potassium will not be in third period as it is in 4th period. all others will be in third period