the description of atomic particles of two elements X and Y is given below:

X Y

protons 8 8

neutrons 8 9

electrons 8 8

i) what is the atomic number of Y?

ii) what is the mass number of X?

iii) what is the relation between X and Y?

iv) which element/elements do they represent?

v) write the electronic configuration of X.

vi) write the cation/anion formed by the element.

(i) Atomic number of Y is 8 and atomic number of X is also 8.

(ii) Mass number of X is 8+8=16 [protons+neutrons=mass number] and mass number of Y = 8 +9 = 17

(iii) Mass number of both X and Y is 16 and 17 respectively , while the atomic number of both X and Y is 8. So these elements are isotopes.

(iv) X represents O=16 [Oxygen]. The answer is O=17 [Oxygen], there are a total of 9 Neutrons and 8 Protons. When you add them up, you get 17. Also O=17 is the isotopes of Oxygen.

(v) Electronic configuration of 2,6 . It is same for both isotopes.

(vi) Oxygen, when in an ionic compound, such as FeO or Na2O, it is formally a anion (i.e. O2-).
Oxygen generally exist as O2- anion.
The cation of oxygen is only formed in case of OF2, where oxygen is in +2 oxidation state i.e. O2+

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