Question 1

Which of the following best explains why Mendeleev is credited with the development of the periodic table over Meyer, even though both independently proposed similar arrangements?

Accepted Answer

Mendeleev predicted the existence and properties of undiscovered elements based on chemical properties.

Question 2

Which equation correctly represents the effective nuclear charge ($$Z_{	ext{eff}}) $$experienced by a valence electron?

Accepted Answer

$$Z_{	ext{eff}} = Z - S$$

Question 3

Which of the following trends is correct for the first ionization energy ($$I_1) $$across a period and down a group in the periodic table?

Accepted Answer

$$I_1$$ increases across a period and decreases down a group.

Question 4

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

Accepted Answer

Cations lose their outermost electron(s), reducing electron-electron repulsion.

Question 5

Consider the isoelectronic series: $$O^{2-}$$, $$F^-$$, $$Na^+$$, $$Mg^{2+}$$, $$Al^{3+}. $$Which ion has the smallest radius and why?

Accepted Answer

$$Al^{3+}$$, because it has the greatest number of protons attracting the same number of electrons.

Question 6

Which property is most characteristic of metals compared to nonmetals?

Accepted Answer

Good electrical conductivity

Question 7

A sample of sodium metal reacts vigorously with water. Which property of sodium explains this behavior?

Accepted Answer

Low first ionization energy

Question 8

Which of the following statements about electron affinity is correct?

Accepted Answer

Electron affinity generally becomes more negative across a period, with exceptions in groups 2A, 5A, and 8A.

Question 9

Which of the following oxides is most likely to react with water to form a basic solution?

Accepted Answer

$$Na_2O$$

Question 10

Why do the alkali metals (Group 1A) have lower melting points and densities compared to the alkaline earth metals (Group 2A)?

Accepted Answer

Alkali metals have only one valence electron, resulting in weaker metallic bonding.

Question 11

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

Accepted Answer

Atomic radius decreases due to increasing effective nuclear charge.

Question 12

Which of the following elements is most likely to form a $$2-$$ anion?

Accepted Answer

Oxygen

Question 13

Which of the following best explains why noble gases have very low chemical reactivity?

Accepted Answer

They have full valence shells, resulting in high ionization energies and positive electron affinities.

Question 14

Which of the following is a property of metalloids that makes them useful in the electronics industry?

Accepted Answer

They are electrical semiconductors.

Question 15

Which of the following best describes the electron configuration change when a magnesium atom forms a $$Mg^{2+}$$ ion?

Accepted Answer

Two electrons are lost from the $$3s$$ orbital.

Question 16

Which of the following best explains the large jump in ionization energy between the removal of the last valence electron and the first core electron?

Accepted Answer

Core electrons are closer to the nucleus and experience a much higher effective nuclear charge.

Question 17

Which of the following reactions represents the formation of a superoxide by potassium?

Accepted Answer

$$2K + O_2$ \rightarrow 2KO_2$$

Question 18

Which of the following best explains why the electron affinity of Group 2A elements is positive or close to zero?

Accepted Answer

The $$s$$ sublevel is full, making it energetically unfavorable to add another electron.

Question 19

Which of the following statements about the chemical behavior of hydrogen is correct?

Accepted Answer

Hydrogen can form both $$H^+$$ and $$H^-$$ ions depending on the reaction partner.

Question 20

Which of the following best describes the trend in metallic character across the periodic table?

Accepted Answer

Metallic character decreases from left to right across a period and increases down a group.

Chapter 7: Periodic Properties of the Elements – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards