Question 1

Which statement best describes the significance of Mendeleev’s periodic table in the development of chemistry?

Accepted Answer

It arranged elements by increasing atomic mass and predicted the existence and properties of undiscovered elements.

Question 2

Which quantum number primarily determines the energy level of an electron in an atom?

Accepted Answer

The principal quantum number $n$

Question 3

What is the electron configuration of a neutral germanium (Ge) atom, and how many unpaired electrons does it have?

Accepted Answer

$1s^22s^22p^63s^23p^64s^23d^{10}4p^2$; 2 unpaired electrons

Question 4

Which of the following best explains why atomic radius decreases across a period from left to right?

Accepted Answer

The effective nuclear charge increases, pulling electrons closer to the nucleus.

Question 5

Which element would have the highest first ionization energy among the following: Na, Mg, Al, Si, P?

Accepted Answer

P

Question 6

What is the effect of electron shielding on the effective nuclear charge ($Z_{eff}$) experienced by a valence electron?

Accepted Answer

Shielding decreases $Z_{eff}$, reducing the attraction between the electron and the nucleus.

Question 7

Which of the following ions is expected to be largest in size: $Na^+$, $Mg^{2+}$, $F^-$, $O^{2-}$?

Accepted Answer

$O^{2-}$

Question 8

Which orbital has the greatest penetration toward the nucleus in a given principal energy level?

Accepted Answer

$s$ orbital

Question 9

Which of the following elements is most likely to form a $-1$ anion?

Accepted Answer

Fluorine

Question 10

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

Accepted Answer

$[Ar]3d^6$

Question 11

Which of the following best describes the trend in metallic character across a period?

Accepted Answer

Metallic character decreases from left to right.

Question 12

Which of the following elements has the smallest atomic radius: S, Ca, F, Rb, Si?

Accepted Answer

F

Question 13

Which statement about the electron configuration of transition metals is correct?

Accepted Answer

Electrons are removed from the $s$ orbital before the $d$ orbital when forming cations.

Question 14

Which of the following is a consequence of the Pauli Exclusion Principle?

Accepted Answer

Electrons in the same orbital must have opposite spins.

Question 15

Which element is expected to have the most negative electron affinity in its period?

Accepted Answer

Chlorine

Question 16

What is the expected charge of the ion formed by rubidium (Rb) in chemical reactions?

Accepted Answer

$+1$

Question 17

Which of the following best explains why noble gases are generally unreactive?

Accepted Answer

They have a stable, full valence shell electron configuration.

Question 18

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

Accepted Answer

Sulfur

Question 19

Which of the following best describes the trend in first ionization energy down a group?

Accepted Answer

It decreases because valence electrons are farther from the nucleus.

Question 20

Which of the following is the correct shorthand electron configuration for aluminum (Al)?

Accepted Answer

$[Ne]3s^23p^1$

Chapter 3: Periodic Properties of the Elements – Study Notes

Study Guide - Practice Questions