Question 1

Which of the following is the correct electron configuration for Tin ($Z = 50$) using the noble gas core shorthand notation?

Accepted Answer

$[Kr] 5s^2 4d^{10} 5p^2$

Question 2

Which neutral element has the following electron configuration: $[Ar] 4s^2 3d^{10} 4p^2$?

Accepted Answer

Germanium (Ge)

Question 3

Is selenium paramagnetic or diamagnetic? Explain your reasoning.

Accepted Answer

Paramagnetic, because it has unpaired electrons in the $4p$ orbital.

Question 4

Which of the following ions is isoelectronic with $Zn^{2+}$?

Accepted Answer

$Br^-$

Question 5

Arrange the following elements in order of increasing atomic radius: $O$, $S$, $P$, $K$, $Cl$. Which has the largest atomic radius?

Accepted Answer

$K > S > P > Cl > O$

Question 6

Which ion would possess the larger ionic radius: $Ca^{2+}$ or $Sc^{2+}$? Explain your reasoning.

Accepted Answer

$Ca^{2+}$, because it has fewer protons and the same number of electrons, resulting in less effective nuclear charge.

Question 7

Using Slater's rules, determine the effective nuclear charge ($Z_{eff}$) on the $4p$ electron in Ga ($Z = 31$).

Accepted Answer

$Z_{eff} \approx 4.3$

Question 8

Which of the following sets of quantum numbers is NOT allowed?

Accepted Answer

$n = 1$, $l = 1$, $m_l = 0$, $m_s = +1/2$

Question 9

Which of the following best describes the trend in atomic radius across a period from left to right?

Accepted Answer

Atomic radius decreases due to increasing effective nuclear charge.

Question 10

Which of the following elements is most likely to be paramagnetic?

Accepted Answer

Oxygen ($O$)

Question 11

What is the maximum number of electrons that can occupy the $3d$ subshell?

Accepted Answer

$10$

Question 12

Which of the following ions has the smallest ionic radius?

Accepted Answer

$Al^{3+}$

Question 13

Which of the following elements has the highest first ionization energy?

Accepted Answer

Oxygen ($O$)

Question 14

Which of the following best explains why $Br^-$ is isoelectronic with $Zn^{2+}$?

Accepted Answer

Both have 36 electrons and the same electron configuration as $Kr$.

Question 15

Which of the following elements has a filled $3d$ subshell in its ground state?

Accepted Answer

Zinc ($Zn$)

Question 16

Which of the following quantum numbers describes the orientation of an orbital in space?

Accepted Answer

$m_l$

Question 17

Which of the following elements would have the greatest number of unpaired electrons in its ground state?

Accepted Answer

Phosphorus ($P$)

Question 18

Which of the following best describes the electron configuration of $Ni$ ($Z = 28$)?

Accepted Answer

$[Ar] 4s^2 3d^8$

Question 19

Which of the following elements is most likely to form a $2+$ cation?

Accepted Answer

Calcium ($Ca$)

General Chemistry: Atomic Structure, Electron Configuration, and Periodic Trends Study Notes

Study Guide - Practice Questions