Chemical Bond Examples in Chemistry

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Chemical Bond.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Chemistry.

Concept Recap

A lasting force of attraction between atoms that holds them together in molecules, compounds, or crystal lattices, formed when atoms share electrons (covalent bond), transfer electrons (ionic bond), or pool electrons (metallic bond).

The 'glue' that holds atoms together, made by sharing or transferring electrons.

Read the full concept explanation →

How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Chemical Bond starts by identifying valence electrons, likely charges or sharing, and the structure that follows.

Common stuck point: Students often know a formula related to chemical bond but skip the recognition step: Am I explaining a substance by electron behavior, bond type, molecular shape, polarity, or attractions between particles? That leads to a correct-looking substitution attached to the wrong chemical model.

Sense of Study hint: Ask: Am I explaining a substance by electron behavior, bond type, molecular shape, polarity, or attractions between particles?

Worked Examples

Example 1

easy
What are the three main types of chemical bonds? Give an example of each.

Answer

Ionic (NaCl), Covalent (H2O), Metallic (Cu)\text{Ionic (NaCl), Covalent (H}_2\text{O), Metallic (Cu)}

First step

1
Ionic bond: transfer of electrons between a metal and nonmetal (e.g., NaCl).

Full solution

  1. 2
    Covalent bond: sharing of electrons between nonmetals (e.g., H2O\text{H}_2\text{O}).
  2. 3
    Metallic bond: delocalized electron sea among metal atoms (e.g., Cu metal).
Chemical bonds form because the resulting arrangement is more stable (lower energy) than separate atoms. The type of bond depends on the electronegativity difference between the atoms involved.

Example 2

medium
Predict the type of bond formed between: (a) Na and Cl, (b) H and O, (c) C and C. Use electronegativity values: Na = 0.9, Cl = 3.0, H = 2.1, O = 3.5, C = 2.5.

Example 3

medium
Using electronegativities (H = 2.1, F = 4.0), classify the H–F bond.

Example 4

hard
Estimate ΔH\Delta H for H2+Cl2→2HClH_2 + Cl_2 \to 2HCl given bond energies (kJ/mol): H–H 436, Cl–Cl 242, H–Cl 431.

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy
Will potassium (K) and bromine (Br) form an ionic or covalent bond? Explain.

Example 2

medium
Why do atoms form chemical bonds instead of always staying separate?

Example 3

easy
What is a chemical bond, in one sentence?

Example 4

easy
Name the two main bond types formed by sharing versus transferring electrons.

Example 5

easy
Does breaking a chemical bond require energy or release energy?

Example 6

easy
Does forming a chemical bond release or absorb energy?

Example 7

easy
What drives most atoms to form chemical bonds?

Example 8

easy
Which bond type forms between a metal and a nonmetal?

Example 9

easy
Which bond type forms between two nonmetals?

Example 10

easy
What is the third major bond type, found in metals?

Example 11

medium
Predict the bond type in MgCl2\text{MgCl}_2 and justify using element types.

Example 12

medium
Predict the bond type in CH4\text{CH}_4 and justify.

Example 13

medium
Why do ionic compounds have higher melting points than many molecular (covalent) substances?

Example 14

medium
In a reaction, breaking reactant bonds absorbs 400 kJ and forming product bonds releases 500 kJ. Is the reaction exo- or endothermic, and by how much?

Example 15

medium
Classify the bonding in copper metal (Cu) and explain its electrical conductivity.

Example 16

medium
Determine the bond type in potassium iodide (KI) and predict whether it conducts electricity when molten.

Example 17

medium
Both NaCl\text{NaCl} (ionic) and diamond (covalent network) are hard with high melting points. What does this say about generalizing 'covalent is weak'?

Example 18

medium
Predict the bond type in water H2O\text{H}_2\text{O} and justify using element types.

Example 19

medium
Why does diamond (pure carbon) have an extremely high melting point despite being covalent?

Example 20

challenge
A reaction breaks bonds totaling 700 kJ and forms bonds totaling 650 kJ. State the net energy and whether bonds in products are, on average, stronger or weaker.

Example 21

challenge
Explain why magnesium oxide (MgO\text{MgO}) has a much higher melting point than sodium chloride (NaCl\text{NaCl}), both ionic.

Example 22

challenge
A solid does not conduct electricity when solid but conducts when molten, is brittle, and has a high melting point. What bond type is it, and why each clue fits?

Example 23

easy
Classify the bond in NaF\text{NaF}.

Example 24

easy
Classify the bond in Cl2\text{Cl}_2.

Example 25

easy
Which bond type best explains why copper wire conducts electricity?

Example 26

easy
O2\text{O}_2 has how many shared electron pairs between the two O atoms?

Example 27

medium
Why is the bond in CO2\text{CO}_2 polar but the molecule nonpolar overall?

Example 28

medium
Compare the bonding in diamond vs. graphite. Both are pure carbon.

Example 29

medium
Predict the bond type in CaF2\text{CaF}_2 and predict whether it conducts when molten.

Example 30

medium
A reaction breaks bonds with total energy 950 kJ and forms bonds with total energy 1100 kJ. State ΔH\Delta H and label exothermic/endothermic.

Example 31

medium
Why are metals malleable while ionic crystals are brittle?

Example 32

medium
In NH3\text{NH}_3, are the bonds covalent or ionic? Justify.

Example 33

medium
Order the bonds by typical strength: H–H, O=O, N≡\equivN.

Example 34

hard
SiO2\text{SiO}_2 has a melting point near 1700 °C while CO2\text{CO}_2 sublimes at -78 °C. Both contain Group 14 elements bonded to O. Explain.

Example 35

hard
Why does LiF\text{LiF} have a higher melting point than LiCl\text{LiCl} even though both are ionic with the same cation?

Example 36

hard
Why does HF\text{HF} have a higher boiling point than HCl\text{HCl} despite weaker H–Cl bond polarity claims?

Example 37

hard
A solid is shiny, malleable, and conducts electricity in both solid and molten form. What bonding does it have?

Example 38

hard
Use Lewis structures to determine the number of lone pairs around the central atom in H2O\text{H}_2\text{O}.

Example 39

hard
In benzene (C6H6C_6H_6), why do all C–C bond lengths equal each other, intermediate between single and double?

Example 40

challenge
Predict whether CCl4\text{CCl}_4 is polar or nonpolar and justify with geometry.

Example 41

challenge
Explain why the H–H bond (436 kJ/mol) is much weaker than the N≡\equivN bond (946 kJ/mol) but the H–H bond is far easier to break in everyday chemistry.
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Background Knowledge

These ideas may be useful before you work through the harder examples.

electronvalence electron