Worksheet: Covalent Bonding

In this worksheet, we will practice describing covalent bonds in terms of the electrostatic attraction between atomic nuclei and a shared electron pair.

Q1:

How many electrons are shared in a triple bond between two nitrogen atoms?

Q2:

How many electrons are shared in a double bond between two oxygen atoms?

Q3:

How many electrons are shared in a single bond between two hydrogen atoms?

Q4:

Which of the following pairs of atoms are most likely to form a covalent bond?

  • ATwo metal atoms
  • BTwo non-metal atoms
  • CA metal atom and a non-metal atom

Q5:

Which of the following pairs of elements is likely to bond covalently?

  • A M g and Cl
  • B F e and H
  • C S and Ne
  • D B a and K
  • E P and F

Q6:

The word “covalent” can be broken into two parts: “co” and “valent.” The “co” part means “together.” To what does the “valent” part refer?

  • AOuter electrons
  • BAtoms
  • CProtons
  • DNuclei
  • EInner electrons

Q7:

Like hydrogen atoms, atoms of sodium each contain a single valence electron. Which of the following is the best description of bonding between sodium atoms?

  • AThe valence electrons of sodium are delocalized, producing a lattice stabilized by metallic bonding.
  • BThe valence electrons of sodium atoms are not involved in bonding.
  • CThe valence electrons of sodium atoms are shared, producing diatomic molecules with single covalent bonds.
  • DThe valence electrons of sodium atoms are shared, producing diatomic molecules with double covalent bonds.
  • EThe valence electrons of sodium are removed, producing a lattice stabilized by ionic bonding.

Q8:

Halogen atoms form diatomic molecules with single covalent bonds. Shown in the graph are the atomic radii of three halogen elements and the bond energies of their diatomic molecules.

What is the main reason for the variation in bond energy between Cl2 and I2?

  • A Bonds become weaker because the separation of nuclei and bonding electrons increases, reducing the electrostatic attraction between them.
  • B Bonds become stronger because the separation of bonding electrons increases, reducing the electrostatic repulsion between them.
  • C Bonds become stronger because the separation of nuclei and bonding electrons increases, reducing the electrostatic repulsion between them.
  • D Bonds become weaker because the separation of nuclei increases, reducing the electrostatic attraction between them.
  • E Bonds become stronger because the separation of nuclei increases, reducing the electrostatic repulsion between them.

Q9:

Iodine monochloride (ICl) is a diatomic molecule with a single polar covalent bond. Electrons are more strongly attracted to the chlorine atom. This polarity may be represented by labeling the structural formula with an arrow, as shown.

I Cl

In which of the following structural formulas is the covalent bond polarity not correctly labeled?

  • A
    H Cl
  • B
    Cl F
  • C
    Br I
  • D
    H F
  • E
    Br Cl

Q10:

Which of the following substances contains polar covalent bonds?

  • A H 2
  • B H O 2
  • C N a O 2
  • D O 2
  • E N a H

Q11:

Which of the following substances contains both covalent and ionic bonds?

  • A C O 2
  • B H C O 2 3
  • C B a C O 3
  • D B a O
  • E H O 2

Q12:

Boron is a semimetal (metalloid), while magnesium is a metal. In boron trichloride (BCl)3, an atom of boron forms 3 polar covalent bonds with chlorine atoms. How is the bonding in magnesium chloride (MgCl)2 different from that in BCl3?

  • AElectrons are attracted more strongly toward the Cl atoms, producing more polar covalent bonds.
  • BElectrons are attracted more strongly toward the Cl atoms, producing less polar covalent bonds.
  • CElectrons are transferred completely from Cl to Mg, producing ionic bonds.
  • DElectrons are attracted less strongly toward the Cl atoms, producing less polar covalent bonds.
  • EElectrons are transferred completely from Mg to Cl, producing ionic bonds.

Q13:

Fluorine forms a diatomic molecule with a single covalent bond.

Why do fluorine atoms in this molecule form only one covalent bond?

  • ASharing 2 electrons between atoms allows each atom to gain a stable octet in its outer shell.
  • BSharing 1 electron between atoms allows each atom to gain a stable octet in its outer shell.
  • CSharing 1 electron between atoms allows each atom to gain a stable pair in its outer shell.
  • DSharing 2 electrons between atoms allows each atom to gain a stable pair in its outer shell.

Which of the following elements also forms a diatomic molecule with a single covalent bond?

  • A K r
  • B H e
  • C N a
  • D B r
  • E S

Q14:

Oxygen forms a diatomic molecule with a double covalent bond. The structural formula for diatomic oxygen is shown.

O O

Why do oxygen atoms in this molecule form more than 1 covalent bond?

  • AThere are 6 valence electrons in the oxygen atom, so 2 electrons must be shared between atoms to produce stable octets in their outer shells.
  • BThere are 2 valence electrons in the oxygen atom, so sharing 4 electrons between atoms fully utilizes their outer shells.
  • CThere are 6 valence electrons in the oxygen atom, so 4 electrons must be shared between atoms to produce stable octets in their outer shells.
  • DThere are 2 valence electrons in the oxygen atom, so sharing 2 electrons between atoms fully utilizes their outer shells.
  • EThere are 4 valence electrons in the oxygen atom, so 4 electrons must be shared between atoms to produce stable octets in their outer shells.

Which of the following elements also commonly forms a diatomic molecule with more than 1 covalent bond?

  • A B e
  • B N e
  • C C
  • D N
  • E F

Q15:

The stability of a covalent bond depends on the balance of attractive and repulsive forces between the electrons and nuclei of the bonding atoms.

Which of the following is an accurate description of the attractive and repulsive forces in a covalent bond?

  • AElectrons are repelled by the nucleus and by each other.
  • BElectrons are attracted to the nucleus and repelled by each other.
  • CElectrons are attracted to the nucleus and to each other.
  • DElectrons are repelled by the nucleus and attracted to each other.

Which particles interact to produce the force of attraction between atoms in a covalent bond?

  • AElectrons and neutrons
  • BProtons and protons
  • CElectrons and electrons
  • DProtons and electrons
  • EProtons and neutrons

Q16:

In a covalent bond, nuclei (x) interact with an energy 𝐸x-x, electrons (e) interact with an energy 𝐸e-e, and electrons and nuclei interact with an energy 𝐸e-x. The total interaction energy, 𝐸total, is determined by the balance of these interaction energies, as illustrated in the figure.

An interaction energy is positive if it is repulsive and negative if it is attractive.

Which interaction energies are negative?

  • A 𝐸 e - x , 𝐸 e - e
  • B 𝐸 e - x
  • C 𝐸 x - x , 𝐸 e - e
  • D 𝐸 e - x , 𝐸 x - x , 𝐸 e - e
  • E 𝐸 e - e

Write an expression for 𝐸total in terms of the interaction energies listed.

  • A 𝐸 = 2 𝐸 + 2 𝐸 4 𝐸 t o t a l e - e x - x e - x
  • B 𝐸 = 𝐸 + 𝐸 + 4 𝐸 t o t a l e - e x - x e - x
  • C 𝐸 = 2 𝐸 2 𝐸 + 2 𝐸 t o t a l e - e x - x e - x
  • D 𝐸 = 𝐸 + 𝐸 + 𝐸 t o t a l e - e x - x e - x
  • E 𝐸 = 𝐸 + 𝐸 𝐸 t o t a l e - e x - x e - x

If a covalent bond is stable, which of the following conditions must be satisfied?

  • A 𝐸 < 0 t o t a l
  • B 𝐸 < 𝐸 t o t a l e - x
  • C 𝐸 > 0 t o t a l
  • D 𝐸 > 𝐸 t o t a l x - x
  • E 𝐸 = 0 t o t a l

Q17:

Hydrogen fluoride is a polar covalent compound with the following structural formula.

H F

Which of the following is the best description of the covalent bond in this molecule?

  • AThe H atom attracts bonding electrons more strongly and has a partial positive charge.
  • BThe F atom attracts bonding electrons more strongly and has a partial negative charge.
  • CThe F atom attracts bonding electrons more strongly and has a partial positive charge.
  • DThe F atom attracts bonding electrons more strongly and is neutral in charge.
  • EThe H atom attracts bonding electrons more strongly and has a partial negative charge.

Q18:

In the molecule borane (BH)3, boron forms single covalent bonds with 3 hydrogen atoms. The structural formula of borane is shown.

B H H H

Why does the boron atom in borane form only 3 single covalent bonds?

  • AThere are 6 valence electrons in the boron atom, so forming 3 covalent bonds fully utilizes its outer shell.
  • BThere are 3 valence electrons in the boron atom, so forming 3 covalent bonds allows it to gain a stable octet in its outer shell.
  • CThere are 6 valence electrons in the boron atom, so forming 3 covalent bonds allows it to gain a stable octet in its outer shell.
  • DThere are 5 valence electrons in the boron atom, so forming 3 covalent bonds allows it to gain a stable octet in its outer shell.
  • EThere are 3 valence electrons in the boron atom, so forming 3 covalent bonds fully utilizes its outer shell.

Q19:

Which of the following compounds is the most covalent?

  • A G e C l 4
  • B L a C l 3
  • C P C l 3
  • D M g C l 2
  • E C C l 4

Q20:

Hydrogen forms a diatomic molecule with a single covalent bond, as shown.

H H

How does covalent bonding increase the stability of the hydrogen atoms?

  • ASharing 2 electrons between atoms allows each atom to gain a stable pair in its outer shell.
  • BSharing 1 electron between atoms allows each atom to gain a stable pair in its outer shell.
  • CSharing 1 electron between atoms allows each atom to gain a stable octet in its outer shell.
  • DSharing 2 electrons between atoms allows each atom to gain a stable octet in its outer shell.

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