Question 1

The electron affinities of elements are always positive.

Accepted Answer

The electron affinity of an element is the energy change that occurs when an electron is added to a neutral atom in the gas phase to form a negatively charged ion. The values of electron affinities can be either positive or negative. A positive value of electron affinity indicates that energy is released when an electron is added, while a negative value indicates that energy must be supplied to the system. Therefore, the statement "the electron affinities of elements are always positive" is false.

Question 2

When metallic hydrides are heated, they
A) decompose explosively to yield metal oxides.
B) liberate oxygen and hydrogen.
C) liberate hydrogen.
D) produce hydrogen ions.
E) do not change because they are extremely stable.

Accepted Answer

Metallic hydrides are compounds of hydrogen with metals. When they are heated, they can liberate hydrogen gas, leaving behind the corresponding metal. For example, sodium hydride (NaH) can be heated to produce hydrogen gas and sodium metal: 2 NaH → 2 Na + H2. However, they do not decompose explosively to yield metal oxides or liberate oxygen and hydrogen. They also do not produce hydrogen ions, since hydrogen in metallic hydrides is in the form of hydride ions (H-).

Question 3

Which of the following exists mainly as cations in compounds?
A) P
B) Ga
C) As
D) Si
E) Sr

Accepted Answer

Sr is a metal and typically forms cations in compounds. The other elements listed are metalloids or nonmetals and are less likely to form cations in compounds.

Question 4

Trends in electron affinity are similar to those for ionization energy.

Accepted Answer

Trends in electron affinity are similar to those for ionization energy in that both generally increase going from left to right across a period and decrease going down a group on the periodic table.

Question 5

Aluminum oxide dissolves in aqueous base .What are the products of this reaction? A) Al(OH₂)₆³⁺(aq) and H₂(g) B) Al₂O₃(s) and H₂(g) C) Al(OH₂)₆³⁺(aq) and O₂(g) D) Al(OH)₄^-(aq) and H₂(g) E) Al(OH)₄^-(aq) and O₂(g)

Accepted Answer

When aluminum oxide (Al2O3) dissolves in an aqueous base, it forms the aluminate ion, Al(OH)4^-, and hydrogen gas, H2(g).

Question 6

AlS1U1B12S1U1B0OS1U1B13S1U1B0(s) dissolves in aqueous acid to produce
A) Al(OHS1U1B12S1U1B0)S1U1B16S1U1B0S1U1P13+S1S1P0(aq).
B) Al(OH)S1U1B14S1U1B0S1U1P1-S1S1P0(aq) and OS1U1B12S1U1B0(g).
C) Al(OH)S1U1B14S1U1B0S1U1P1-S1S1P0(aq).
D) Al(OHS1U1B12S1U1B0)S1U1B16S1U1B0S1U1P13+S1S1P0(aq) and HS1U1B12S1U1B0(g).
E) Al(OH)S1U1B14S1U1B0S1U1P1-S1S1P0(aq) and HS1U1B12S1U1B0(g).

Accepted Answer

AlS1U1B12S1U1B0OS1U1B13S1U1B0(s) dissolves in aqueous acid to produce Al(OHS1U1B12S1U1B0)S1U1B16S1U1B0S1U1P13+S1S1P0(aq).

Question 7

Write an equation for the second ionization energy of magnesium.

Accepted Answer

The answer of Write an equation for the second ionization...

Question 8

Which of the following pairs of elements both have acidic oxides?
A) Ca and As
B) Mg and Al
C) B and Li
D) In and Sn
E) P and Se

Accepted Answer

Phosphorus (P) and Selenium (Se) both form acidic oxides. Phosphorus oxide (P4O10) and selenium dioxide (SeO2) are examples of acidic oxides, reacting with water to form phosphoric acid (H3PO4) and selenous acid (H2SeO3), respectively.

Question 9

The valence electrons of elements in the lower left of the periodic table experience the greatest effective nuclear charge.

Accepted Answer

Elements in the lower left of the periodic table have a low effective nuclear charge due to the shielding effect of inner electrons. Therefore, the valence electrons in these elements experience the least effective nuclear charge. Valence electrons in elements in the upper right of the periodic table, where the effective nuclear charge is highest, experience the greatest effective nuclear charge.

Question 10

Which of the following is a basic oxide? A) CaO(s) B) CO₂(g) C) SO₂(g) D) CO(g) E) SiO₂(s)

Accepted Answer

A basic oxide is an oxide that reacts with an acid to form a salt and water. Calcium oxide (CaO) is a classic example of a basic oxide since it reacts with an acid to form calcium salts and water.

Question 11

Which of the following does not act as a Lewis acid? A) Na₂O B) NO C) NO₂ D) SO₃ E) CO₂

Accepted Answer

NaSbB12O19 is a type of tungstate, which is not known to act as a Lewis acid. The other options all contain elements (N, S, O, or C) that can act as Lewis acids.

Question 12

Which of the following has the smallest polarizability?
A) CaS1U1P12+S1S1P0
B) SS1U1P12-S1S1P0
C) Cl
D) S

Accepted Answer

Polarizability is the ease with which the electron cloud of an atom or molecule can be distorted by an applied electric field. The polarizability of an ion is generally smaller than that of the corresponding neutral atom or molecule. Among the given options, CaS1U1P12+S1S1P0 is an ion, while SS1U1P12-S1S1P0, Cl, and S are neutral molecules. Therefore, CaS1U1P12+S1S1P0 has the smallest polarizability.

Question 13

Which of the following does not form a saline hydride?
A) Lithium
B) Barium
C) Calcium
D) Magnesium
E) Beryllium

Accepted Answer

Beryllium does not form a saline hydride; it forms covalent hydrides due to its small size and high ionization energy.

Question 14

Which of the following pairs of elements have similar polarizability?
A) Be and Al
B) Li and Na
C) B and Al
D) Be and Mg
E) Mg and B

Accepted Answer

The answer of Which of the following pairs of elements...

Question 15

Circle the species that has the largest radius: CaS1U1P12+S1S1P0,SS1U1P12-S1S1P0,S,Cl.

Accepted Answer

The answer of Circle the species that has the largest...

Question 16

Which of the following has the largest atomic radius?
A) In
B) Ga
C) Ge
D) Al

Accepted Answer

Indium (In) has the largest atomic radius among the options given. This is because atomic radius generally increases as you move down a group in the periodic table. Indium is below gallium (Ga), germanium (Ge), and aluminum (Al) in group 13, making it the element with the largest atomic radius among the choices.

Question 17

All of the oxides of the following elements are amphoteric except
A) P
B) Ga
C) As
D) Sb

Accepted Answer

Phosphorus (P) primarily forms acidic oxides, not amphoteric oxides, unlike gallium (Ga), arsenic (As), and antimony (Sb), which can form oxides that exhibit amphoteric behavior.

Question 18

Write the formula of the hydride ion.

Accepted Answer

The answer of Write the formula of the hydride ion....

Question 19

Which of the following is an acidic oxide? A) CaO(s) B) MgO(s) C) Bi₂O₃(s) D) Na₂O(s) E) SiO₂(s)

Accepted Answer

The only oxide that can be considered acidic is one that can react with water to form an acid. Non-metal oxides are generally considered acidic oxides, while metal oxides are basic. Of the choices given, only SiO2 is a non-metal oxide, making it the only acidic oxide.

Question 20

Which of the following compounds is predicted to have bonds with the most covalent character? A) MgF₂ B) LiF C) CsI D) MgI₂ E) BaBr₂

Accepted Answer

The answer of Which of the following compounds is predicted...

Quiz 8: The Main-Group Elements

The electron affinities of elements are always positive.

When metallic hydrides are heated, they

Which of the following exists mainly as cations in compounds?

Trends in electron affinity are similar to those for ionization energy.

Aluminum oxide dissolves in aqueous base .What are the products of this reaction?

Al₂O₃(s) dissolves in aqueous acid to produce

Write an equation for the second ionization energy of magnesium.

Which of the following pairs of elements both have acidic oxides?

The valence electrons of elements in the lower left of the periodic table experience the greatest effective nuclear charge.

Which of the following is a basic oxide?

Which of the following does not act as a Lewis acid?

Which of the following has the smallest polarizability?

Which of the following does not form a saline hydride?

Which of the following pairs of elements have similar polarizability?

Circle the species that has the largest radius: Ca²⁺,S^2-,S,Cl.

Which of the following has the largest atomic radius?

All of the oxides of the following elements are amphoteric except

Write the formula of the hydride ion.

Which of the following is an acidic oxide?

Which of the following compounds is predicted to have bonds with the most covalent character?

Quiz 8: The Main-Group Elements

The electron affinities of elements are always positive.

When metallic hydrides are heated, they

Which of the following exists mainly as cations in compounds?

Trends in electron affinity are similar to those for ionization energy.

Aluminum oxide dissolves in aqueous base .What are the products of this reaction?

Al2O3(s) dissolves in aqueous acid to produce

Write an equation for the second ionization energy of magnesium.

Which of the following pairs of elements both have acidic oxides?

The valence electrons of elements in the lower left of the periodic table experience the greatest effective nuclear charge.

Which of the following is a basic oxide?

Which of the following does not act as a Lewis acid?

Which of the following has the smallest polarizability?

Which of the following does not form a saline hydride?

Which of the following pairs of elements have similar polarizability?

Circle the species that has the largest radius: Ca2+,S2-,S,Cl.

Which of the following has the largest atomic radius?

All of the oxides of the following elements are amphoteric except

Write the formula of the hydride ion.

Which of the following is an acidic oxide?

Which of the following compounds is predicted to have bonds with the most covalent character?

Al₂O₃(s) dissolves in aqueous acid to produce

Circle the species that has the largest radius: Ca²⁺,S^2-,S,Cl.