Which of the following elements is the best conductor of electricity? (LO 22.1)

(a) N (b) As

(c) P (d) Bi

Which element will react most vigorously with water, and what is the reaction that occurs?

(a) Lithium; 2 Li(s) + 2 H₂O(l) → 2 Li⁺(aq) + 2 H^–(aq) + H₂O₂(aq)

(b) Potassium; 2 K(s) + 2 H₂O(l) → 2 K⁺(aq) + 2 OH^–(aq) + H₂(g)

(c) Magnesium; Mg(s) + 2 H₂O(l) → Mg²⁺(aq) + 2 OH^–(aq) + H₂(g)

(d) Barium; Ba(s) + 2 H₂O(l) → Ba²⁺(aq) + 2 H^–(aq) + H₂O₂(aq)

Consider the following oxoacids: HClO, HClO2, HClO3, and HClO4. In which oxoacid does chlorine have an oxidation

state of +5? Which oxoacid is the strongest?

(LO 22.17)

(a) HClO has a Cl oxidation state of +5, and HClO4 is the strongest acid.

(b) HClO2 has a Cl oxidation state of +5, and HClO is the strongest acid.

(c) HClO3 has a Cl oxidation state of +5, and HClO4 is the strongest acid.

(d) HClO4 has a Cl oxidation state of +5, and HClO is the strongest acid.

Look at the location of elements A, B, C, and D in the following periodic table:

(a) Write the formula of the simplest binary hydride of each element.

Look at the location of elements A, B, C, and D in the following periodic table:

(d) Which hydrides react with water to give an acidic solution, and which give a basic solution?

Look at the location of elements A, B, C, and D in the following

periodic table:

(c) Which hydrides react with water to give H2 gas? Write a balanced net ionic equation for each reaction.

The following models represent the structures of binary hydrides

of second-row elements:

(a) Identify the nonhydrogen atom in each case, and write the molecular formula for each hydride.

Using the shorthand notation of Figure 22.9, draw the structure of the cyclic silicate anion in which four SiO₄ tetrahedra share O atoms to form an eight-membered ring of alternating Si and O atoms. Give the formula and charge of the anion.

Suggest a plausible structure for the silicate anion in the mineral thortveitite, Sc₂Si₂O₇.

Describe the structures of the white and red allotropes of phosphorus, and explain why white phosphorus is so reactive.

Compare and contrast the properties of ammonia and phosphine.

In what forms is oxygen commonly found in nature?

Arrange the following oxides in order of increasing basic character: Al2O3, Cs2O, K2O, N2O5.

Write a balanced net ionic equation for the reaction of the amphoteric oxide ZnO with:

a. Hydrochloric acid

Write a balanced net ionic equation for the reaction of the amphoteric oxide Ga₂O₃ with:

a. Aqueous sulfuric acid

a. Why is the SO₃ molecule trigonal planar but the SO₃^2– ion is trigonal pyramidal?

Give one example from main-group chemistry that illustrates each of the following descriptions.

d. Polar molecule that violates the octet rule

An important physiological reaction of nitric oxide (NO) is its interaction with the superoxide ion (O₂^–) to form the peroxynitrite ion (ONOO^–).

a. Write electron-dot structures for NO, O₂^–, and ONOO^–, and predict the O–N–O bond angle in ONOO^–.

Locate each of the following elements on the periodic table.

(f) Group 5A element that forms the strongest p bonds

Look at the location of elements A, B, C, and D in the following periodic table:

Which hydride has the lowest boiling point?

In the following pictures of binary hydrides, ivory spheres

represent H atoms or ions, and burgundy spheres represent

atoms or ions of the other element.

(1)

(2)

(3)

(4)

(a) Identify each binary hydride as ionic, covalent, or interstitial.

(b) What is the oxidation state of hydrogen in compounds (1), (2), and (3)? What is the oxidation state of the other

element?

In the following pictures of binary hydrides, ivory spheres

represent H atoms or ions, and burgundy spheres represent

atoms or ions of the other element.

(1)

(2)

(3)

(4)

(b) What is the oxidation state of hydrogen in compounds (1), (2), and (3)? What is the oxidation state of the other

element?

The following models represent the structures of binary hydrides of second-row elements:

b. Draw an electron-dot structure for each hydride. For which hydride is there a problem in drawing the structure? Explain.

The following pictures represent structures of the hydrides of four second-row elements:

(1)

(2)

(3)

(4)

(a) Which compound has the highest melting point?

The following pictures represent structures of the hydrides of four second-row elements:

(1)

(2)

(3)

(4)

(b) Which compound has the lowest boiling point?

Look at the location of elements A, B, C, and D in the following periodic table:

(b) Classify each oxide as basic, acidic, or amphoteric.

Look at the location of elements A, B, C, and D in the following periodic table:

(e) Which of these oxides has the highest melting point? Which has the lowest melting point?

Consider the six second- and third-row elements in groups 4A–6A of the periodic table:

Possible structures for the binary fluorides of each of these elements in its highest oxidation state are shown below.

(a) Identify the nonfluorine atom in each case, and write the molecular formula of each fluoride.

Consider the six second- and third-row elements in groups 4A–6A of the periodic table:

Possible structures for the binary fluorides of each of these elements in its highest oxidation state are shown below.

(b) Explain why the fluorides of nitrogen and phosphorus have different molecular structures but the fluorides of carbon and silicon have the same molecular structure.

Which of the following elements (X) will form a covalent hydride with the formula XH₃ that is a gas at room temperature? (LO 22.4)

(a) Al (b) As (c) Ba (d) Se