Atomic, Ionic, and Molecular Solids - Online Tutor, Practice Problems & Exam Prep

Identify the type (or types) of crystalline solid that possess the following properties:​ good thermal and electrical conductor, can be deformed without breaking.​

Identify the type (or types) of crystalline solid that possess the following properties: typically soft, relatively low melting point, and poor electrical conductor.

Identify the type (or types) of crystalline solid that possess the following properties: poor thermal conductor, hard, and brittle.

Consider the following behaviors of molecules of a liquid crystal at three different temperatures (T₁, T₂, and T₃):

Identify the temperature/s in which the substance exists in a liquid crystalline state and identify the type of liquid crystalline phase shown.

Germanium (Ge) is used in semiconductors and other electronic devices. It has a structure similar to diamond. Is Ge a metallic, ionic, molecular, or covalent-network solid?

At 294.5 K, the compound octylcyanobiphenyl undergoes a phase transition from the crystalline solid phase to a liquid crystal phase. Upon increasing the temperature to 306.5 K, it undergoes another liquid crystal phase transition. 

Identify which among the following diagrams depicts the liquid crystal formed at 306.5 K.

CO₂ is a molecular compound while SiO₂ is a covalent network solid. Why do carbon and silicon bond differently even though they are both group 4A elements?

One form of SiO₂ known as α-quartz is a covalent network solid with a trigonal crystal system. Each Si atom is bonded to four O atoms and each O is bonded to two Si atoms, forming a corner-sharing SiO₄ tetrahedron. Draw a partial structure of SiO₂.

Consider the substances below that have a liquid crystal state. Which compound will have a solid-to-liquid crystal phase change at a higher temperature and why?

Determine if the substance shown below will have a liquid crystalline phase. Justify your answer.

Match the solids PVC (polyvinyl chloride), Ni, CaSO₄, sucrose, and diamond to their correct classifications.

(i) Molecular solid

(ii) Metallic solid

(iii) Covalent network solid

(iv) Amorphous solid

(v) Ionic solid

The melting point of calcium metal is 1115 K while calcium oxide melts at 2886 K. Which is the stronger type of bond, metallic or ionic bonding?

Account for the large difference in the ΔH°_vap of tungsten (774 kJ/mol) and mercury (59 kJ/mol).

Listed below are the Mohs hardness of some Period 5 transition metals. Is the trend best explained by the electron-sea model or MO model?

Which of the Period 4 transition metals would you expect to have the highest melting point? Account for your answer using band theory.

Shown below are MO diagrams for Mg showing two cases: (i) the s and p bands do not overlap, and (ii) the s and p bands overlap. Which MO diagram explains why Mg has a high electrical conductivity?

Which of the following corresponds to the electron distribution in the s–p band of Ga metal.

Explain the difference in the melting points of K (336.7 K) and Ca (1115 K) using the electron-sea model.

Shown below are the electron distributions in the s–d band of three metals. Rank them in order of increasing melting point.

The image below shows the electron distribution in the composite s–d band of an unknown metal. Identify the most likely identity of the metal.

Which of the following correctly explains why boron carbide-reinforced alumina is stronger than pure alumina?

(i) Boron carbide whiskers can redirect cracks preventing them to develop cleanly in one direction. 

(ii) Most of the chemical bonds are aligned opposite the tiny fiber-shaped boron-carbide particles (whiskers) hence giving fibers great strength along that direction. 

(iii) Two sides of a crack can be broken further by boron carbide whiskers by forming bridges preventing further development of cracks. 

Which of the following is the reason why boron/epoxy composites are used as a material for aerospace and military applications?

Write the reaction equation when Sn(OH)₄ sol is converted to a gel. After the gel is heated and dried, provide the formula of the ceramic formed.

Silicon carbide (SiC) is a ceramic used in electronic applications that operate at high temperatures and high voltages. The β-SiC has a zinc blende structure similar to a diamond wherein each Si atom is bonded tetrahedrally to four C atoms and each C atom is also bonded tetrahedrally to four Si atoms. Which of the following statements explains why silicon carbide is generally more brittle than a metal?

A. When stress is applied to silicon carbide it cannot deform to adapt to stress because the strong ionic bond prevents the atoms from slipping past one another.

B. When stress is applied to silicon carbide it cannot deform to adapt to stress because the strong ionic bond allows the atoms from slipping past one another.

C. When stress is applied to silicon carbide it cannot deform to adapt to stress because the strong covalent bond prevents the atoms from slipping past one another.

D. When stress is applied to silicon carbide it cannot deform to adapt to stress because the strong covalent bond allows the atoms from slipping past one another.

Oxide ceramics are more prone to corrosion than metals. Is this statement true or false? Explain.

Which of the following characteristics correctly differentiates a ceramic from a metal?

(i) Metals are generally stiffer than ceramics.

(ii) Ceramics generally have higher melting points than metals.

(iii) Metals are more wear-resistant than ceramics.

(iv) Ceramics are more corrosion-resistant than metals.

Which statement is true regarding intermetallic compounds and alloys?

Which statement is true?

Which attractive force is not present in between the particles of molecular crystals?

Which of the following is a characteristic of an alkali metal?

Identify if the following statement is true or false: A metallic solid becomes softer, more ductile, and will have lower electrical and thermal conductivities when carbon is introduced into the lattice because the atomic orbitals of the carbon atoms do not have the same energy as the metal orbitals.

Which statement is true?

Classify the following fluorides based on their melting points: CF₄ (–183.6°C), NaF (993°C), NF₃ (–206.8°C), MgF₂ (1,263°C).

Which of the following statement is true regarding "colored gold" jewelry?

Identify the correct statement about graphite and diamond. 

True or False. Nonmetals are not used to make alloys.

Which of the following statements is true?

The characteristics of covalent-network solids and ionic solids share some properties such as having high melting points. Which solid would conduct electricity in its molten form?

A substance melts at 3350°C, an excellent thermal conductor but not an electrical conductor. What type of solid is this substance?

What type of alloy is Cu_0.95Sn_0.05?

Consider the 3D structure of the potassium bromide lattice below: 

Identify the expected predominant bonding present in the compound as either ionic, metallic, or covalent.

Which of the following statements is true?

The following images show the properties of metal. Which of the following statement is correct?

Identify the type of solid that has the following characteristics: brittle, very high melting point, and electrical insulators in their solid form.

Identify the type of solid of WO₃ that has a melting point of 1,473 °C as either molecular, metallic, ionic, or covalent-network solid.

Germanium dioxide is used as an optical material for lenses and for the core of fiber-optic lines. Identify the type of solid of GeO₂ as either molecular, metallic, ionic, or covalent-network solid.

Determine if the statement below is true or false and if the statement is false, identify the incorrect part.

Thermosetting plastic, such as Vulcanized rubber, can be reshaped readily.

Which of the following statements is true?

Which of the following statements is true?

Which of the following statement is correct for molecules that exhibit a liquid crystalline phase?

Given the alignment of the molecules in a liquid crystal for three different temperatures

Which of the following is true?

Determine which one of the following has the lowest melting point? C₆H₁₂O₆(s), SiO₂(s), MgCl₂(s), or Xe(s). Explain your answer.

Determine which one of the following has a lower melting point? NO₂(s) or CO₂(s). Explain your answer.

Determine which one of the following has a lower melting point? Na(s) or Rb(s). Explain your answer.

Determine which one of the following has a lower melting point? KBr(s) or CaS(s). Explain your answer.

Classify graphite as an atomic, molecular, or ionic solid.

Classify C₆H₁₂O₆ as an atomic, molecular, or ionic solid.

Classify Li₂SO₄ as an atomic, molecular, or ionic solid.

Ceramics can be classified into three main categories: Oxide ceramics, non-oxide ceramics, and silicate ceramics. Classify ZrSiO₄ as one of the three classes.

Ceramics can be classified into three main categories: Oxide ceramics, non-oxide ceramics, and silicate ceramics. Classify ZrO₂ as one of the three classes.

Ceramics can be classified into three main categories: Oxide ceramics, non-oxide ceramics, and silicate ceramics. Classify Al₄C₃ as one of the three classes.

Platinum has a melting point of 1,768 °C and a bond length of 277.5 pm in platinum metal. What happens to the bond length if platinum was placed under intense pressure?

Identify the number of molecular solids among the compounds below.

GaSb; Cu; FeO₃; CaO₂; glass; sapphire; rust; methane; benzene; Teflon.

What does the chemical formula of an ionic compound represent?

Identify the statement that describes the difference between n-type and p-type semiconductors

Classify each of the given solids as molecular, ionic, or atomic: Br₂(s), SO₂(s), MgCl₂(s), Cu(s)

Chromium has a very high melting point at 1907 °C. The distance between Cr atoms in chromium metal is 252 pm. If you put chromium metal under high pressure, predict what would happen to the distance between Cr atoms.