Chemistry, asked by cokkiearilia, 2 days ago

Aluminium (At. No = 13) and Oxygen (At. No = 8) combine to form
Aluminium oxide.
a. State the electronic configuration of Oxygen.
b. State the number of valence electrons in Aluminium.
c. What is the formula of the compound formed by Aluminium and
Oxygen?

Answers

Answered by abhi178

Given info : aluminium and oxygen combine to form aluminium oxide.

To find :

solution : electron configuration of oxygen : 1s² , 2s² , 2p⁴

valence electrons of an element are the number of electrons in the outermost shell of the element.

atomic no of aluminium = 13

so electronic conguration of aluminium : 1s², 2s², 3p⁶ , 3s² , 3p¹

bolded part is the outermost shell ( two subshells 3s and 3p) and the number of element in the outermost shell is 3.

therefore the number of valence electrons in Aluminium is 3.

aluminium is metal and oxygen is non metal so the compound formed by these elements must be ionic.

aluminium can lose three electrons ∴ oxidation state of aluminium ion , Al³⁺ = +3

oxygen can gain two electrons ∴ oxidation state of oxygen ion, O²⁻ = -2

now the ratio of oxidation state of Al to O = 3 : 2

so the ratio of Al to O in chemical formula would be = 2 : 3

therefore the chemical formula of aluminium oxide is Al₂O₃

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