Question

Neutral atoms of argon, atomic number 18, have the same number of electrons as each of the following items except: K+ Ca+2 Ne Cl- S-2

Answer 1

Neutral atoms of argon, atomic number 18, have the same number of electrons as each of the following items except: Ne

Ne
1s² 2s² 2p⁶

Ar, K(+), Ca(2+), Cl(-), S(2-)
1s² 2s² 2p⁶ 3s² 3p⁶

Answer 2

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, $1s^22s^22p^63s^23p^6$

The number of electrons in argon = 18

The element is, $K^+$

The atomic number of K (potassium) = 19

The electronic configuration of 'K' is, $1s^22s^22p^63s^23p^64s^1$

The electronic configuration of $K^+$ is, $1s^22s^22p^63s^23p^6$

The number of electrons in $K^+$ = 18

The element is, $Ca^{2+}$

The atomic number of Ca (calcium) = 20

The electronic configuration of 'Ca' is, $1s^22s^22p^63s^23p^64s^2$

The electronic configuration of $Ca^{2+}$ is, $1s^22s^22p^63s^23p^6$

The number of electrons in $Ca^+$ = 18

The element is, Neon

The atomic number of neon= 10

The electronic configuration of neon is, $1s^22s^22p^6$

The number of electrons in neon = 10

The element is, $Cl^-$

The atomic number of Cl (chlorine) = 17

The electronic configuration of 'Cl' is, $1s^22s^22p^63s^23p^5$

The electronic configuration of $Cl^-$ is, $1s^22s^22p^63s^23p^6$

The number of electrons in $Cl^-$ = 18

The element is, $S^{2-}$

The atomic number of S (sulfur) = 16

The electronic configuration of 'S' is, $1s^22s^22p^63s^23p^4$

The electronic configuration of $S^{2-}$ is, $1s^22s^22p^63s^23p^6$

The number of electrons in $S^{2-}$ = 18

Therefore, the element that has no same number of electrons as of argon will be, Neon (Ne).