Argon (Ar)

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Practice argon

Questions from the course about argon. If you’re signed in, your answers count toward your progress.

1. Question 1Ground-state electron configurationWarm-up

   Which is the ground-state electron configuration of a neutral argon atom ($\ce{Ar}$)?

   A$[\mathrm{Ne}]\,3s^{2}\,3p^{6}$B$[\mathrm{Ar}]\,4s^{2}$C$[\mathrm{Ar}]\,4s^{1}$D$[\mathrm{Ne}]\,3s^{2}\,3p^{5}$

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2. Question 2Estimate the effective nuclear chargeWarm-up

   Use the simple shielding model $Z_{\text{eff}} = Z - S$, where $S$ is the number of core (inner-shell, $n < 3$) electrons and electrons in the same shell do not shield each other. What is $Z_{\text{eff}}$ for a valence electron of argon ($\ce{Ar}$)?

   Your answer

   Whole number.

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3. Question 3Compare two elements and explainExam level

   Which element has the higher first ionization energy, $\ce{Na}$ or $\ce{Ar}$, and why?

   AAr: it has a larger effective nuclear charge on valence electrons in the same shell (n = 3), so its valence electrons are held more tightly.BNa: first ionization energy decreases from left to right across a period.CAr: it has more occupied electron shells.DNa: it has fewer valence electrons, so each one is held more tightly.

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