Question 1

Which principle states that electrons are added to the lowest energy orbitals first when building up the electron configuration of an atom?

Accepted Answer

Aufbau Principle

Question 2

What is the ground-state electron configuration for a neutral sodium (Na) atom?

Accepted Answer

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

Question 3

Which of the following ions is isoelectronic with neon ($Ne$)?

Accepted Answer

$Na^+$

Question 4

How many valence electrons does phosphorus ($P$) have?

Accepted Answer

5

Question 5

Which electron configuration represents a transition metal with a completely filled $d$ subshell?

Accepted Answer

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

Question 6

Which rule states that no two electrons in an atom can have the same set of four quantum numbers?

Accepted Answer

Pauli Exclusion Principle

Question 7

What is the shorthand electron configuration for selenium ($Se$)?

Accepted Answer

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

Question 8

Which of the following elements has the electron configuration $1s^2\ 2s^2\ 2p^6\ 3s^2\ 3p^6\ 4s^2\ 3d^6$?

Accepted Answer

Iron ($Fe$)

Question 9

When forming cations, which electrons are lost first in transition metals?

Accepted Answer

Electrons from the $s$ subshell of the highest principal quantum number

Question 10

Which of the following ions is diamagnetic?

Accepted Answer

$Zn^{2+}$

Question 11

According to Hund's Rule, when filling degenerate orbitals, electrons will:

Accepted Answer

Fill each orbital singly with parallel spins before pairing

Question 12

What is the charge of the ion formed by a Group 2A alkaline earth metal?

Accepted Answer

2+

Question 13

Which of the following elements has a ground-state electron configuration ending in $3p^3$?

Accepted Answer

Phosphorus ($P$)

Question 14

How many valence electrons does nickel ($Ni$) have, according to its electron configuration $[Ar]\ 4s^2\ 3d^8$?

Accepted Answer

10

Question 15

Which of the following is the correct electron configuration for the $Cl^-$ ion?

Accepted Answer

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

Question 16

Which of the following statements about noble gases is TRUE?

Accepted Answer

They have a completely filled highest principal energy level

Question 17

What is the electron configuration for the $Fe^{2+}$ ion?

Accepted Answer

$[Ar]\ 3d^6$

Question 18

Which of the following elements is paramagnetic in its ground state?

Accepted Answer

Iron ($Fe$)

Question 19

Which of the following best explains why $4s$ electrons are lost before $3d$ electrons when transition metals form cations?

Accepted Answer

The $4s$ orbital is higher in energy than the $3d$ orbital after electron filling

Question 20

Which of the following ions has the same number of electrons as $Ar$?

Accepted Answer

$Cl^-$

Electron Configuration, Quantum Numbers, and Periodic Table Structure

Study Guide - Practice Questions