Question 1

Which of the following electron configurations violates the Aufbau Principle?

Accepted Answer

$1s^2\ 2s^2\ 2p^3\ 3s^1$

Question 2

What is the ground state electron configuration for fluorine ($Z = 9$)?

Accepted Answer

$1s^2\ 2s^2\ 2p^5$

Question 3

Which of the following is the correct condensed electron configuration for aluminum ($Z = 13$)?

Accepted Answer

$[Ne]\ 3s^2\ 3p^1$

Question 4

Which element has the following ground state electron configuration: $[Ar]\ 4s^2\ 3d^{10}\ 5p^2$?

Accepted Answer

Tin (Sn)

Question 5

Which of the following orbital diagrams correctly represents the electron configuration for phosphorus ($Z = 15$)?

Accepted Answer

Three unpaired electrons in the $3p$ orbitals

Question 6

Which of the following best describes the Aufbau Principle?

Accepted Answer

Electrons fill the lowest energy orbitals first before moving to higher energy orbitals.

Question 7

What is the condensed electron configuration for zinc ($Z = 30$)?

Accepted Answer

$[Ar]\ 4s^2\ 3d^{10}$

Question 8

Which of the following statements about condensed electron configurations is correct?

Accepted Answer

They use the symbol of the nearest noble gas in brackets to represent core electrons.

Question 9

Which of the following electron configurations represents a violation of Hund's Rule?

Accepted Answer

$1s^2\ 2s^2\ 2p^4$\ with two electrons paired in one $2p$ orbital and the other two $2p$ electrons unpaired

Question 10

Which element has the following condensed electron configuration: $[Xe]\ 6s^2\ 4f^{14}\ 5d^{10}\ 6p^2$?

Accepted Answer

Lead (Pb)

Question 11

A chemist is analyzing an unknown element and finds its electron configuration is $[Ar]\ 4s^2\ 3d^6$. Which element is this?

Accepted Answer

Iron (Fe)

Question 12

Which of the following is the correct electron configuration for a manganese(II) ion ($Mn^{2+}$, $Z = 25$)?

Accepted Answer

$[Ar]\ 3d^5$

Question 13

Which of the following best explains why the $4s$ orbital is filled before the $3d$ orbital?

Accepted Answer

The $4s$ orbital is lower in energy than the $3d$ orbital when empty.

Question 14

Which of the following is the correct electron configuration for chlorine ($Z = 17$)?

Accepted Answer

$1s^2\ 2s^2\ 2p^6\ 3s^2\ 3p^5$

Question 15

Which of the following is the correct condensed electron configuration for manganese ($Z = 25$)?

Accepted Answer

$[Ar]\ 4s^2\ 3d^5$

Question 16

Which of the following is the correct order of filling for the first four subshells according to the Aufbau Principle?

Accepted Answer

$1s \rightarrow 2s \rightarrow 2p \rightarrow 3s$

Question 17

Which of the following elements has a valence electron configuration of $ns^2\ np^3$?

Accepted Answer

Phosphorus (P)

Question 18

Which of the following is the correct electron configuration for a $Zn^{2+}$ ion?

Accepted Answer

$[Ar]\ 3d^{10}$

Question 19

Which of the following is the correct condensed electron configuration for lead ($Z = 82$)?

Accepted Answer

$[Xe]\ 6s^2\ 4f^{14}\ 5d^{10}\ 6p^2$

Electron Configuration and the Aufbau Principle: Study Notes

Study Guide - Practice Questions