Question 1

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

Accepted Answer

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

Question 2

Which element would you expect to have the most exothermic (most negative) electron affinity?

Accepted Answer

S

Question 3

What is the correct electron configuration for a ground-state Cu atom?

Accepted Answer

$$[Ar] 4s^1$ 3d$$^{10}$$

Question 4

Which of the following ions is isoelectronic with Ar?

Accepted Answer

$$K^+$$

Question 5

Which of the following elements is expected to be paramagnetic?

Accepted Answer

O

Question 6

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 because valence electrons are farther from the nucleus.

Question 7

Which of the following elements has the highest metallic character?

Accepted Answer

Rb

Question 8

Which of the following statements about transition metal electron configurations is correct?

Accepted Answer

Some transition metals have anomalous configurations to achieve half-filled or fully filled d sublevels.

Question 9

Which of the following sets is correctly ordered by increasing atomic radius?

Accepted Answer

Mg \u003c Ca \u003c Sr

Question 10

Which of the following best explains why the first ionization energy of B is less than that of Be?

Accepted Answer

The electron removed from B is in a 2p orbital, which is higher in energy and less penetrating than the 2s orbital of Be.

Question 11

Which of the following ions has the largest radius?

Accepted Answer

$$S^{2-}$$

Question 12

Which of the following elements is most likely to form a $$2+$$ cation?

Accepted Answer

Mg

Question 13

What is the noble gas core electron configuration for iodine (I)?

Accepted Answer

$$[Kr] 5s^2$ 4d$$^{10}$$ 5p^5$

Question 14

Which of the following best describes the trend in density for elements in a group as you move down the periodic table?

Accepted Answer

Density increases because atomic mass increases more rapidly than atomic volume.

Question 15

Which of the following elements is a metalloid?

Accepted Answer

Si

Question 16

Which of the following is the correct order of filling for the first four energy sublevels according to the Aufbau principle?

Accepted Answer

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

Question 17

Which of the following best describes the Pauli exclusion principle?

Accepted Answer

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

Question 18

Which of the following elements has the greatest effective nuclear charge experienced by its valence electrons?

Accepted Answer

S

Question 19

Which of the following is a property of nonmetals?

Accepted Answer

Tend to gain electrons in chemical reactions

Question 20

Which of the following best explains why cations are smaller than their parent atoms?

Accepted Answer

Cations have more protons than electrons, increasing effective nuclear charge and pulling electrons closer.

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

Study Guide - Practice Questions