What is the valency ?if the element X combines with another element Y whose electronic configuration is 2,8,7 what will be the formula of the compound thus formed ?
State how you arrived to this formula.
Answers
Answer:
combining capacity of an element is called valency..
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Thus both will combine to form HCl compound. Which is hydrochloric acid.
Explanation:
Combining capacity of an element with another element to complete its valance shell is to form molecules or compounds is called valency.
As the electronic configuration 2,8,7 shows that the atomic number of the element is 17 which is chlorine.
Chlorine has 7 electrons in its valance shell and it require one more electron to complete its valance shell.
Let's say the element Y = Cl
Element X = H
Electronic configuration of Cl = 2, 8 , 7
Electronic configuration of H = 1
Hydrogen will donate its one electron to Chlorine to complete its valence shell and will get an electron in return to complete it own valence shell to attain stability. Thus both will combine to form HCl compound.