Answer : The element that has no same number of electrons as of argon will be, Neon (Ne).
Explanation :
The element is, Argon
The atomic number of argon = 18
The electronic configuration of argon is, [tex]1s^22s^22p^63s^23p^6[/tex]
The number of electrons in argon = 18
The element is, [tex]K^+[/tex]
The atomic number of K (potassium) = 19
The electronic configuration of 'K' is, [tex]1s^22s^22p^63s^23p^64s^1[/tex]
The electronic configuration of [tex]K^+[/tex] is, [tex]1s^22s^22p^63s^23p^6[/tex]
The number of electrons in [tex]K^+[/tex] = 18
The element is, [tex]Ca^{2+}[/tex]
The atomic number of Ca (calcium) = 20
The electronic configuration of 'Ca' is, [tex]1s^22s^22p^63s^23p^64s^2[/tex]
The electronic configuration of [tex]Ca^{2+}[/tex] is, [tex]1s^22s^22p^63s^23p^6[/tex]
The number of electrons in [tex]Ca^+[/tex] = 18
The element is, Neon
The atomic number of neon= 10
The electronic configuration of neon is, [tex]1s^22s^22p^6[/tex]
The number of electrons in neon = 10
The element is, [tex]Cl^-[/tex]
The atomic number of Cl (chlorine) = 17
The electronic configuration of 'Cl' is, [tex]1s^22s^22p^63s^23p^5[/tex]
The electronic configuration of [tex]Cl^-[/tex] is, [tex]1s^22s^22p^63s^23p^6[/tex]
The number of electrons in [tex]Cl^-[/tex] = 18
The element is, [tex]S^{2-}[/tex]
The atomic number of S (sulfur) = 16
The electronic configuration of 'S' is, [tex]1s^22s^22p^63s^23p^4[/tex]
The electronic configuration of [tex]S^{2-}[/tex] is, [tex]1s^22s^22p^63s^23p^6[/tex]
The number of electrons in [tex]S^{2-}[/tex] = 18
Therefore, the element that has no same number of electrons as of argon will be, Neon (Ne).
