Chemical Bonding — EOY Practice
Secondary 3 Chemistry — MCQ & structured questions
Prepared by Miss Clarissa Ng
www.clartutors.com
www.clartutors.com
Which of the following is true for covalent and ionic substances?
Which of the following elements in Period 3 of the Periodic Table is likely to have the highest melting point?
The table below shows the properties of four substances.
Which of the following statements about the structure of the substances is true?
Talc is an ionic mineral which when crushed forms talcum powder. It has the formula Mg3Si4O10(OH)2. What is the charge on the silicate group [Si4O10]?
Which of the following statements is incorrect about iodine, I2?
The bond strength of a covalent bond is loosely associated with the size of the atoms. Generally, smaller atoms form stronger covalent bonds. Which of the following combinations are arranged correctly according to their bond strengths in increasing order?
Which of the following is not true about a molecule of ammonia, NH3?
Which of the following best describes the properties of carbon dioxide?
Element P and Q form a compound with formula PQ3. This compound exists as a liquid at room temperature. What are the correct electron arrangements of atoms P and Q?
An investigation of the properties of the third-period elements shows that the boiling points of sodium chloride and silicon tetrachloride are 1465°C and 57°C respectively. What is the reason for the difference in boiling points?
Which statements are correct? 1 All elements exist as atoms. 2 All molecules are compounds. 3 All substances with ionic bonding are compounds.
The following table shows the number of protons for elements P, Q, R and S.
Which two elements will react to form a compound with a low melting point?
How many electrons are not involved in covalent bonding in a hydrazine, N2H4 molecule?
A covalent oxide compound has the chemical formula P2O. What could be the electronic configuration of atom P?
Which compound contains both ionic and covalent bonds?
Three statements on metallic bonding are shown. I. They are electrostatic in nature. II. The metal ions are delocalised. III. Its strength is directly proportional to the magnitude of the charge of the ions. Which statement(s) is/are correct?
Which statement is correct for magnesium fluoride?
Which property do all metals have?
What happens when potassium bromide melts?
Which pair will conduct electricity because they both contain mobile ions?
The melting point of calcium oxide is much higher than the melting point of sodium oxide. Which statement explains this?
Which of the following statements provides the best explanation for the solubility of ionic compounds in water?
Each of the four molecules below is isolated in the gaseous state. Which species has an atom that does not obey the octet rule?
Calcium and sulfur are two elements in the Periodic Table.
State the number of protons and valence electrons of a sulfur atom. [2]
Draw a Lewis diagram to show the bonding in calcium sulfide. [1]
Explain if you would expect calcium sulfide to conduct electricity at room temperature, referring to its bonding and structure. [2]
“Titanium white” is a white pigment made up of titanium dioxide, TiO2, which is produced from titanium tetrachloride, TiCl4. The table below shows some properties of TiCl4.
Suggest the structure of TiCl4, giving reasons for your answer. [3]
Napoleon died in 1821 and analysis of his hair samples later showed high levels of arsenic. Arsenic exists in three common allotropes: metallic grey, yellow, and black arsenic. Arsenic is prepared by heating arsenic(III) oxide with carbon. The poisoning could have been deliberate or accidental. If deliberate, arsenic(III) oxide was probably used. It could have been accidental if the poisonous gas arsine, AsH3, was released from the blue copper(II) arsenate(III) used to decorate his prison cell.
Identify the allotrope which is most likely to be an electrical conductor and suggest a reason for its high conductivity in its solid state. [2]
Draw a Lewis diagram, showing the arrangement of the valence electrons in a molecule of the covalent compound, arsine, AsH3. It has a simple molecular structure. [1]
Explain, in terms of bonding and structure, why arsine is a gas at room temperature and is insoluble in water. [3]
Trichloromethane, CHCl3, also known as chloroform, was used as an anaesthetic in surgery. It is not used today as it naturally reacts with oxygen in air to form a highly toxic gas phosgene, COCl2 and hydrogen chloride gas. In phosgene, the carbon atom is in the centre of the molecule and is attached to both chlorine atoms and to the oxygen atom.
Draw a Lewis structure of the phosgene molecule. [1]
State the number of sigma (σ) bonds and the number of pi (π) bonds present in a single phosgene molecule. [1]
Suggest the shape of the phosgene molecule and explain how you derive at your answer. [2]
Explain why phosgene molecule is polar. [1]
Bond length is the distance between the nuclei of two atoms that are covalently bonded to each other. The table below lists the bond length and bond energy of some covalently-bonded atoms.
Deduce the relationship between the number of bonds between two atoms, and the bond energy. [1]
List one set of bonds, consisting of 2 or more bonds from the table, that you had used in order to make your deduction in (a)(i). [1]
What is the relationship between bond length, and the number of bonds between the same type of atoms? [1]
Suggest a reason for your answer to (b)(i). [2]
Generally, the length of the bond between two atoms is approximately the sum of the covalent radii of the two atoms. Hence, use effective nuclear charge to explain general trends for bond lengths across a period, for bonds between the same type of atoms. [3]
Ammonium chloride is a white crystalline salt used mainly as a fertiliser and a flavouring agent.
State the type of bonding(s) found in ammonium chloride. [1]
Ammonium chloride decomposes to form hydrogen chloride gas. Draw a dot-and-cross diagram to show the bonding in hydrogen chloride gas, showing only the valence electrons. [2]
The properties of some substances are shown in the table below.
In hydrogen iodide, the hydrogen and iodine atoms are held together by covalent bonds. Define covalent bond. [2]
Given that hydrogen iodide is a strong acid, predict and explain its electrical conductivity in the aqueous state. Illustrate your answer with an equation. [2]
Explain the difference in electrical conductivity of substance X in the solid and liquid states. [3]
Explain why substance Y has a high melting point. [2]
Explain what is unusual about the bonding present in aluminium chloride. [1]
Group 17 elements show trends in their melting points and boiling points. Table 1
Describe and explain the trend in boiling point down the group 17 elements. [3]
Metallic aluminium is very reactive with atmospheric oxygen to form a thin layer of aluminium oxide, Al2O3, which is resistant to corrosion.
In the space below, draw the “dot and cross” diagram of aluminium oxide. [2]
The melting points of two elements belonging to Period 3, silicon and chlorine, are shown in the table below.
With reference to their structure and bonding, explain the difference in melting points between silicon and chlorine. [4]
The relative electrical conductivities of some metals in Period 4 of the Periodic Table are shown below.
Describe, with the aid of a well-labelled diagram in the box below, the structure and bonding of metals. [2]
By stating the number of valence electrons, suggest a reason for the difference in electrical conductivity between potassium and calcium metal. [2]
With reference to its bonding, explain how carbon nanotubes are able to conduct electricity. [3]
Borospherene, B40, is a new molecule discovered in 2014. It is a hollow, cage-like molecule of 40 boron atoms held together by covalent bonds, similar in shape to a football.
In terms of its structure, explain why borospherene is expected to have poor electrical conductivity. [2]
State and explain whether borospherene is expected to have a high or low boiling point. [2]
Predict and explain whether the boiling point of borospherene is expected to be higher or lower than that of methane, CH4. [2]
By considering the number of valence electrons that boron has, explain why the bonding between boron atoms in borospherene is unusual. [1]
This question is about transition metals and the ions they form.
One property that transition metals share with a Group 2 metal like magnesium is their high melting point. Explain why transition metals have high melting point. [2]
Draw a dot-and-cross diagram to show the bonding in zinc chloride, ZnCl2. Show only the valence electrons. [1]
Oxalic acid, H2C2O4, reacts with acidified manganate(VII) ions according to the ionic equation below: 2MnO4-(aq) + 16H+(aq) + 5C2O4 2-(aq) → 2Mn2+(aq) + 10CO2(g) + 8H2O(l)
Draw the Lewis diagram for CO2 and predict its shape and bond angle. [4]
Barium carbonate reacts with dilute hydrochloric acid to form barium chloride, carbon dioxide and water. Carbon dioxide and water are both simple covalent compounds.
Explain, in terms of intermolecular forces, why the two simple covalent products formed in (a) exist as different states of matter at r.t.p.. [2]
The melting points of sodium and magnesium are 371 K and 923 K respectively.
State and explain the difference in melting point between sodium and magnesium. [3]
Group 15 elements react with hydrogen to form hydrides. The type of bond formed can be determined by the difference in electronegativity.
Define the term electronegativity. [2]
Using the VSEPR theory, draw the Lewis structure of the NH3 molecule and state its bond angle and shape. [4]
The ‘lead’ in a pencil is made of a mixture of graphite and clay.
When the percentage of graphite is increased, the pencil ‘lead’ slides across the paper more easily. Explain this observation using the structure and bonding present in graphite. [2]
Graphite is an allotrope of carbon. Carbon nanotubes are also allotropes of carbon — a sheet of hexagonal rings of carbon atoms rolled into a tube. Based on this structure, would you expect its melting point to be high or low? Explain. [2]
α-Sn (grey tin) is the stable form below 13°C and has a diamond-like structure. β-Sn (white tin) is metallic and has a close-packed lattice. Deduce which allotrope of tin is malleable. [1]
Based on the information above, suggest a use for the allotrope in (d)(i). [1]
Nitrogen reacts with hydrogen to form ammonia in the presence of finely divided iron according to the equation shown. N2+ 3H2 ⇌ 2NH3 Fig 3.1 shows the volume of ammonia formed when 300 cm3 of hydrogen and 200 cm3 of nitrogen were added to the reacting mixture.
Draw a dot-and-cross diagram to show the bonding in nitrogen. Show only the valence electrons. [1]
History of the Singapore coins. The three series of the one-dollar Singapore coins have been developed over time. The first and second series consist of alloys.
Use ideas of structure to explain why a mixture of metals, rather than pure metals, are used to make the first and second series of one-dollar Singapore coins. [2]
Use ideas of bonding to explain why metals have low coefficient of thermal expansion. [1]
Carbon (diamond) has the lowest known CTE of all naturally occurring materials, but polymers such as poly(tetrafluoroethene) typically have high CTE. Use ideas of structure and bonding to explain this difference in property. [3]
Silicon carbide is an important ceramic material in the industry because of its very low coefficient of thermal expansion. It is formed when carbon and silicon react together, and it has a giant covalent structure in which each carbon atom is bonded to four silicon atoms and each silicon atom to four carbon atoms. Suggest two other properties of silicon carbide that make it suitable for use as a ceramic material. [2]