Question 1

Which of the following best explains why elements in the same group of the periodic table have similar chemical properties?

Accepted Answer

They have the same number of valence electrons.

Question 2

Which of the following electron configurations represents a transition metal in its ground state?

Accepted Answer

$1s^2\ 2s^2\ 2p^6\ 3s^2\ 3p^6\ 4s^2\ 3d^5$

Question 3

According to Coulomb’s Law, what happens to the potential energy of two oppositely charged particles as they get closer together?

Accepted Answer

The potential energy decreases.

Question 4

Which of the following statements about the Pauli Exclusion Principle is correct?

Accepted Answer

No two electrons in an atom can have the same four quantum numbers.

Question 5

Which element would you expect to have the largest atomic radius?

Accepted Answer

K

Question 6

What is the correct electron configuration for a Br atom?

Accepted Answer

$1s^2\ 2s^2\ 2p^6\ 3s^2\ 3p^6\ 4s^2\ 3d^{10}\ 4p^5$

Question 7

Which of the following ions is isoelectronic with Argon ($Ar$)?

Accepted Answer

$K^+$

Question 8

A main-group element has an outer electron configuration of $ns^2\ np^4$. What charge is likely for an ion of this element?

Accepted Answer

$2-$

Question 9

Which of the following best describes the trend in first ionization energy as you move down a group in the periodic table?

Accepted Answer

It decreases.

Question 10

Which of the following elements is expected to have the highest electron affinity?

Accepted Answer

Cl

Question 11

Which of the following ions is expected to be paramagnetic?

Accepted Answer

$Fe^{3+}$

Question 12

Why does sodium ($Na$) commonly form a $1+$ ion and not a $2+$ ion?

Accepted Answer

Sodium has only one valence electron that is easily removed; removing a second electron would be more difficult because it would be a core electron.

Question 13

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

Accepted Answer

Metallic character decreases.

Question 14

Which of the following statements about the atomic radii of isoelectronic species is correct?

Accepted Answer

The species with the lowest atomic number has the largest radius.

Question 15

Which of the following is the correct order of filling for atomic orbitals according to the aufbau principle?

Accepted Answer

$1s\ 2s\ 2p\ 3s\ 3p\ 4s\ 3d\ 4p$

Question 16

Which of the following best explains why the 2s orbital is lower in energy than the 2p orbital in multi-electron atoms?

Accepted Answer

The 2s orbital is closer to the nucleus and experiences less shielding.

Question 17

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

Accepted Answer

Cl

Question 18

Which of the following best describes the difference between core and valence electrons?

Accepted Answer

Valence electrons are in the outermost shell and participate in bonding, while core electrons are in inner shells and do not participate in bonding.

Question 19

Which of the following elements has a large jump between its third and fourth ionization energies, indicating it has three valence electrons?

Accepted Answer

B

Question 20

Which of the following best explains why valence electrons are more important than core electrons in determining the reactivity and bonding in atoms?

Accepted Answer

Since bonding involves the transfer or sharing of electrons, valence electrons are most important because they are held most loosely.

Periodic Properties of the Elements: Structure, Electron Configuration, and Trends

Study Guide - Practice Questions