Worksheet: Valency

In this worksheet, we will practice using the group of a nonmetal in the periodic table to calculate the maximum number of covalent bonds it may form.

Q1:

The valence shell of boron is the second electron shell and contains 3 electrons. How many covalent bonds can boron form by sharing its electrons?

Q2:

Hydrogen has a single electron in its valence shell. How many covalent bonds can it form?

Q3:

The valence shell of oxygen is the second electron shell and contains 6 electrons. How many covalent bonds can oxygen form?

Q4:

The valence shell of carbon is the second electron shell and contains 4 electrons. How many covalent bonds can carbon form?

Q5:

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

  • ANeon and argon
  • BNitrogen and oxygen
  • CSulfur and chlorine
  • DCarbon and fluorine
  • EBoron and hydrogen

Q6:

Which of the following statements about chemical bonding is false?

  • AIn covalent bonding, electrons are shared between atoms.
  • BMolecular compounds can only contain covalent or ionic bonding, never both.
  • CIn ionic bonding, electrons are transferred between atoms, forming ions.
  • DChemical bonding involves electrostatic attractions between oppositely charged particles.
  • EIn metallic bonding, a sea of delocalized electrons is formed.

Q7:

How many electrons does an atom of strontium lose when forming the ionic compound SrI2?

Q8:

How many atoms of bromine are usually needed to form an ionic compound with a single atom of aluminum?

Q9:

The Lewis structure for a molecular compound of potassium and sulfur is shown below. How can you tell this compound is ionically bonded?

  • AIonic compounds always contain atoms in a 21 ratio.
  • BThe atoms are sharing electrons to obtain full outer shells but have not become ions.
  • CSulfur atoms can only form ionic bonds.
  • DThe atoms have either lost or gained electrons to become ions and obtain full outer shells.
  • EThe atoms are surrounded by a sea of delocalized electrons.

Q10:

Which of the following is the correct Lewis structure for a fluoride ion?

  • A
  • B
  • C
  • D
  • E

Q11:

The Lewis structure for an atom of helium is shown below. Which of these statements explains why helium does not usually form chemical bonds?

He
  • AThe first electron shell can hold eight electrons, but finding six electrons for a full valence shell is too difficult.
  • BHelium is too small to form chemical bonds with atoms of other elements.
  • CThe first electron shell can only hold two electrons; therefore, helium has a full valence shell.
  • DHelium is a gas and therefore cannot lose its two electrons.
  • EHelium changes into hydrogen when it loses one of its electrons.

Q12:

Which of the following is the correct Lewis structure for an atom of nitrogen?

  • A
    N
  • B
    N
  • C
    N
  • D
    N
  • E
    N

Q13:

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.

Q14:

Which type of chemical bonding does not involve electrostatic attraction between the positively charged nuclei and the negatively charged electrons?

  • ACovalent
  • BIonic
  • CMetallic

Q15:

Which of the following is not a type of chemical bonding?

  • AMetallic
  • BIonic
  • CNuclear
  • DCovalent

Q16:

Which of the following pairs of atoms are unlikely to form an ionic compound?

  • ACalcium and oxygen
  • BLithium and sulfur
  • CMagnesium and chlorine
  • DGallium and fluorine
  • ESodium and aluminum

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