Question 1

Which of the following best describes a periodic property of the elements?

Accepted Answer

A property that is predictable based on an element’s position on the periodic table.

Question 2

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

Accepted Answer

The potential energy decreases.

Question 3

Which of the following statements about Mendeleev’s periodic table is correct?

Accepted Answer

He arranged elements in order of increasing mass and left gaps for undiscovered elements.

Question 4

Which element is a transition metal?

Accepted Answer

Cr

Question 5

Which of the following electron configurations represents a noble gas?

Accepted Answer

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

Question 6

Which of the following best explains why the atomic radius increases as you move down a group in the periodic table?

Accepted Answer

The principal quantum number $$n$$ increases, placing valence electrons farther from the nucleus.

Question 7

Which of the following ions is expected to be paramagnetic?

Accepted Answer

An ion with one or more unpaired electrons

Question 8

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

Accepted Answer

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

Question 9

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

Accepted Answer

2+

Question 10

Which of the following elements has the highest first ionization energy?

Accepted Answer

S

Question 11

Which of the following best explains why sodium commonly forms 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 12

Which of the following statements about electron affinity is correct?

Accepted Answer

Electron affinity generally becomes more negative across a period.

Question 13

Which of the following elements is expected to have the most metallic character?

Accepted Answer

Rb

Question 14

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

Accepted Answer

Atomic radius decreases due to increasing effective nuclear charge.

Question 15

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

Accepted Answer

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

Question 16

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.

Question 17

Which of the following pairs is isoelectronic?

Accepted Answer

Na$$^+$$ and Ne

Question 18

Which of the following statements about the effective nuclear charge ($$Z_{	ext{eff}}) is $$correct?

Accepted Answer

$$Z_{	ext{eff}}$$ increases across a period and decreases down a group.

Question 19

Which of the following elements would you expect to have the largest atomic radius?

Accepted Answer

Se

Question 20

Which of the following best describes the electron configuration of a Cr atom, considering the known anomalies in transition metals?

Accepted Answer

$$[Ar]\ 4s^1$\ 3d^5$

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

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