Question 1

Which statement best describes the periodic law as established by Mendeleev?

Accepted Answer

Elements are arranged by increasing atomic number, resulting in periodic repetition of chemical properties.

Question 2

What is the maximum number of electrons that can occupy a single orbital, according to the Pauli exclusion principle?

Accepted Answer

$2$

Question 3

Which quantum number determines the shape of an orbital?

Accepted Answer

Angular momentum quantum number $l$

Question 4

An atom has the electron configuration $1s^2 2s^2 2p^6 3s^2 3p^5$. Which element is this?

Accepted Answer

Chlorine $(Cl)$

Question 5

Which of the following ions is paramagnetic?

Accepted Answer

$Fe^{3+}$

Question 6

What is the correct order of filling for the following orbitals according to the Aufbau principle?

Accepted Answer

$4s \rightarrow 3d \rightarrow 4p$

Question 7

Which element has the highest first ionization energy?

Accepted Answer

Neon $(Ne)$

Question 8

What is the trend in atomic radius as you move down a group in the periodic table?

Accepted Answer

Atomic radius increases due to addition of electron shells.

Question 9

Which statement best explains why $Na^+$ is smaller than $Na$?

Accepted Answer

$Na^+$ has fewer electrons, resulting in less electron-electron repulsion.

Question 10

Which of the following best describes the concept of effective nuclear charge ($Z_{eff}$)?

Accepted Answer

The net positive charge experienced by an electron after accounting for shielding by other electrons.

Question 11

Which of the following elements is most likely to form a $2^+$ cation with a noble gas configuration?

Accepted Answer

Magnesium $(Mg)$

Question 12

Which of the following statements about electron affinity is correct?

Accepted Answer

Electron affinity generally becomes more exothermic across a period.

Question 13

Which of the following elements is most metallic?

Accepted Answer

Cesium $(Cs)$

Question 14

Which electron configuration represents a diamagnetic atom?

Accepted Answer

$1s^2 2s^2 2p^6$

Question 15

Which of the following best explains the trend in ionization energy across a period?

Accepted Answer

Ionization energy increases due to increased effective nuclear charge ($Z_{eff}$).

Question 16

Which of the following statements about the $d$ block of the periodic table is correct?

Accepted Answer

It contains the transition metals.

Question 17

A neutral atom of sulfur has how many valence electrons?

Accepted Answer

$6$

Question 18

Which of the following best describes the difference between paramagnetic and diamagnetic species?

Accepted Answer

Paramagnetic species have unpaired electrons; diamagnetic species have all electrons paired.

Question 19

Which of the following ions is larger than its parent atom?

Accepted Answer

$Cl^-$

Question 20

Which of the following best explains why the second ionization energy of sodium is much higher than the first?

Accepted Answer

The second electron is removed from a noble gas configuration, which is very stable.

Chem chapter 3 study guide

Study Guide - Practice Questions