Chemical Bond

Bonding
definition

Also known as: bond

Grade 9-12

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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. Chemical bonds determine every physical and chemical property of a substance: its melting point, hardness, conductivity, and reactivity.

Definition

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.

💡 Intuition

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

🎯 Core Idea

Bonds form because atoms are more stable with certain electron arrangements.

Example

H–H bond in \text{H}_2, O–H bonds in water, \text{Na}^+\text{Cl}^- ionic bond in salt.

Notation

Bonds are drawn as lines between atoms in structural formulas: single bond (—), double bond (=), triple bond (\equiv). Bond energy is measured in kJ/mol. Bond length is measured in picometers (pm) or angstroms.

🌟 Why It Matters

Chemical bonds determine every physical and chemical property of a substance: its melting point, hardness, conductivity, and reactivity. Understanding bonds explains why diamond is hard (strong covalent network), why metals conduct electricity (metallic bonds), and why salt dissolves in water (ionic bonds break apart).

💭 Hint When Stuck

When identifying bond types, look at the atoms involved. First check if it is between a metal and nonmetal (likely ionic). Then check if it is between two nonmetals (likely covalent). Finally, determine if the electronegativity difference is large (>1.7 = ionic), medium (0.4-1.7 = polar covalent), or small (<0.4 = nonpolar covalent).

Formal View

A chemical bond is an interatomic force arising from the electrostatic interaction between nuclei and electrons. Bond energy is the energy required to break one mole of bonds in the gas phase. The three primary types are ionic (electron transfer), covalent (electron sharing), and metallic (electron delocalization).

🚧 Common Stuck Point

Breaking bonds requires energy; forming bonds releases energy.

⚠️ Common Mistakes

  • Thinking breaking bonds releases energy — breaking bonds always requires energy input; it is forming bonds that releases energy
  • Believing ionic bonds are weaker than covalent bonds — ionic bonds in a crystal lattice are very strong, which is why ionic compounds have high melting points
  • Forgetting metallic bonding as a third major type — metals form bonds through a 'sea of delocalized electrons,' not through sharing or transfer

Frequently Asked Questions

What is Chemical Bond in Chemistry?

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.

When do you use Chemical Bond?

When identifying bond types, look at the atoms involved. First check if it is between a metal and nonmetal (likely ionic). Then check if it is between two nonmetals (likely covalent). Finally, determine if the electronegativity difference is large (>1.7 = ionic), medium (0.4-1.7 = polar covalent), or small (<0.4 = nonpolar covalent).

What do students usually get wrong about Chemical Bond?

Breaking bonds requires energy; forming bonds releases energy.

How Chemical Bond Connects to Other Ideas

To understand chemical bond, you should first be comfortable with electron and valence electron. Once you have a solid grasp of chemical bond, you can move on to ionic bond, covalent bond and metallic bond.

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Visualization

Static

Visual representation of Chemical Bond