Learning Objective

In this lesson we will learn about the different types of chemical bonds that can exist between atoms and the different types of chemical structures atoms can form.

Learning Outcomes

By the end of this lesson you will be able to:

  • Describe metallic, ionic and covalent bonding.
  • Describe properties of monatomic, metallic, ionic, covalent molecular and covalent network structures.
  • Identify the type of chemical bonding in different elements and compounds.
  • Explain how the type of bonding and structures an element forms is related to its location on the periodic table.

Chemical Bonding and Structures

1 | Overview of Chemical Bonding and Structures

2 | Metallic Bonding and Structures

3 | Ionic and Covalent Bonding

4 | Ionic Bonding and Structures

5 | Covalent Bonding and Structures

6 | Monatomic Structures

7 | Bonding, Electron Configuration and the Periodic Table

8 | Summary

 

 chemical bonding and structures worksheet  year 10 chemistry pdf workbook  Year 10 Chemistry Print Workbook Australian Curriculum

Click images to preview the worksheet for this lesson and the Year 10 Chemistry Workbook (PDF and print versions)

 


Atoms

  • Most atoms do not exist as separate particles.
  • More often, they are connected to other atoms by chemical bonds, forming molecules or lattices.
  • These molecules and lattices are fixed arrangements of atoms, which may consist of one type of atom or different types of atoms.

 

Chemical Bonds

  • Chemical bonds are strong forces of attraction between atoms that hold them together.
  • There are three types of chemical bonds:
  • Metallic bonds.
  • Ionic bonds.
  • Covalent bonds.

 
chemical bond

Chemical bonds are strong forces of attraction between atoms or ions.

 

Chemical Structures

  • The chemical structure of a substance refers to the way atoms are arranged within that substance.
  • The different types of chemical bonds, or the lack thereof, result in five different types of chemical structures:
  • Metallic structures.
  • Ionic structures.
  • Covalent molecular structures.
  • Covalent network structures.
  • Monatomic structures.

 
types of bonding and structures

There are three types of chemical bonds – metallic bonds, ionic bonds and covalent bonds.

 


Metallic Bonding

  • In metals, the valence electrons are free to move between atoms.
  • These electrons surround a lattice of positive metal ions.
  • Metallic bonds are electrostatic forces of attraction between positively charged metal ions and the negatively charged electrons surrounding them.

 
metallic bonding atom lattice

Metallic bonding occurs between positively charged metal ions and negatively charged electrons.

 

Metallic Structures

  • When atoms are joined by metallic bonds they form metallic structures.
  • Metallic structures are rigid lattices of metal ions surrounded by delocalised valence electrons.
  • Metallic structures include metal elements, such as iron (Fe) and copper (Cu), and metal alloys, such as brass and bronze.
  • Metals and metal alloys generally have the following properties:
  • They are solids at room temperature.
  • They conduct electricity and heat.
  • They are malleable (can be bent into shape) and ductile (can be drawn into wires).
  • They have a shiny metallic lustre.

 
metal properties shiny lustre malleable

Metals and metal alloys have distinctive properties, such as being shiny and malleable.

(Image: Qimono, Pixabay)

 


Ionic and Covalent Bonding

  • Apart from metallic bonding, atoms tend to combine with other atoms in ways that result in full valence shells.
  • Having full valence shells makes atoms more stable.
  • Atoms can combine in two different ways to achieve full valence shells:
  • They can gain or lose electrons to form ionic bonds.
  • They can share electrons to form covalent bonds.
  • When metal atoms and non-metal atoms combine, they form ionic bonds.
  • When non-metal atoms combine, they form covalent bonds.
  • Therefore, non-metals (excluding noble gases) can form either ionic or covalent bonds, depending on whether they are combining with metals or non-metals.

 
ionic and covalent bonding

Ionic bonding involves the transfer of electrons between atoms.
Covalent bonding involves the sharing of electrons between atoms.

 


Ionic Bonding

  • Many atoms achieve full valence shells by gaining or losing valence electrons.
  • As a result, they form charged particles called ions.
  • When an atom loses one or more electrons, it forms a positively charged ion (cation).
  • Atoms that can form positive ions include all metals.
  • When an atom gains one or more electrons, it forms a negatively charged ion (anion).
  • Atoms that can form negative ions include non-metals in groups 15-17.
  • Ions formed from single atoms, such as Mg2+ and Br, are known as monatomic ions.
  • Ions formed from multiple atoms, such as NH4+ and SO42– are known as polyatomic ions.
  • Within a polyatomic ion, atoms are held together by covalent bonds.
  • Ionic bonds are electrostatic forces of attraction between positively charged ions and negatively charged ions.
  • When involving only monatomic ions, ionic bonds will be formed between a metal ion and a non-metal ion.
  • Ionic bonds cannot form between two metal ions or between two non-metal ions because metal atoms can only form positive ions and non-metal atoms can only form negative ions.
  • * Hydrogen atoms can form positive ions, but only in solution; therefore, hydrogen does not form ionic bonds – it always forms covalent bonds.
  • Since ionic bonds involve different types of ions, they can only exist in compounds.

 
ionic bonding atom ion arrangement

Ionic bonding occurs between positively charged ions and negatively charged ions.

 

Ionic Structures

  • When ions are joined by ionic bonds they form ionic structures.
  • Ionic structures are orderly, crystalline lattices, consist of alternating positive and negative ions.
  • There are no individual molecules within this type of structure.
  • Ionic structures include ionic compounds, such as sodium chloride (NaCl) and copper sulfate (CuSO4).
  • Chemical formulas for ionic compounds represent ratios of positive and negative ions, rather than structures of molecules.
  • Ionic compounds generally have the following properties:
  • They are hard, brittle solids with high melting points.
  • They are often soluble in water.
  • They do not conduct electricity as solids, but do conduct electricity as molten liquids or aqueous solutions.

 
copper sulfate crystal ionic compound

Ionic compounds, such as copper sulfate, are brittle solids with crystalline structures.

(Image: Ra’ike, Wikimedia Commons)

 


Covalent Bonding

  • Covalent bonds involve the sharing of valence electrons between two non-metal atoms.
  • The sharing of electrons enables these atoms to have full valence shells.
  • For hydrogen, a full outer shell consists of two electrons.
  • For all other non-metals, a full outer shell consists of eight electrons, known as an octet.
  • Covalent bonds can involve the same type of atom or different types of atoms.
  • Therefore, covalent bonds can exist in both elements and compounds.

 
covalent molecule bond

Covalent bonding occurs between two non-metal atoms.

 

Covalent Structures

  • When atoms are joined by covalent bonds they form covalent structures.
  • Covalent structures may be discrete molecules (covalent molecular structures) or continuous networks of atoms (covalent network structures).

 

 covalent molecular structures  covalent-network-structure

Covalent bonding occurs in covalent molecular structures and covalent network structures.

 

Covalent Molecular Structures

  • Covalent molecular structures consist of discrete molecules held together by covalent bonds.
  • Covalent molecular structures may be elements or compounds.
  • Covalent molecular elements include all non-metals in groups 15-17, which contain varying numbers of atoms in each molecule.
  • For example, chlorine (Cl2) exists as molecules containing two chlorine atoms, phosphorus (P4) exists as molecules containing four phosphorus atoms and sulfur (S8) exists as molecules containing eight sulfur atoms.
  • Examples of covalent molecular compounds include water (H2O), ammonia (NH3) and methane (CH4).
  • Covalent molecular elements and compounds generally have the following properties:
  • They have low melting and boiling points and are usually gases or liquids at room temperature, although large organic compounds are often solids.
  • They do not conduct electricity.

 
chlorine covalent molecular compound

Covalent molecular substances, such as chlorine, have low melting and boiling points.

(Image: Larenmclane, Wikimedia Commons)

 

Covalent Network Structures

  • Covalent network structures consist of continuous networks of atoms joined by covalent bonds.
  • Covalent network structures may be elements or compounds.
  • An example of a covalent network element is carbon (C), which exists as continuous networks of carbon atoms covalently bonded to each other.
  • An example of a covalent network compound is silicon dioxide (SiO2), which exists as continuous networks containing silicon atoms and oxygen atoms joined by covalent bonds in a 1:2 ratio.
  • Covalent network elements and compounds generally have the following properties:
  • They are hard solids with high melting points.
  • They are insoluble in water.
  • They do not conduct electricity.
  • They are unreactive.

 
silicon dioxide quartz covalent network compound

Covalent network structures, such as quartz (silicon dioxide), are hard crystalline solids with very high melting points.

(Image: Stux, Pixabay)

 


Monatomic Structures

  • Monatomic structures consist of individual atoms, with no chemical bonds between them.
  • The only elements that exist as separate atoms are the noble gases, which are located in group 18 of the periodic table.
  • These include helium (He), neon (Ne) and argon (Ar).

 
monatomic structures noble gas atoms

Monatomic structures contain no chemical bonds between atoms.

 

  • Monatomic structures have the following properties:
  • They have very low boiling points and are gases at room temperature.
  • They are very unreactive.

 
neon gas monatomic element

Neon gas does not react, but glows red when an electric current is passed through it.

(Image: Pslawinski, Wikimedia Commons)

 


Bonding and Electron Configuration

  • The type of bonding that forms between two atoms depends on the electron configurations of the atoms involved.
  • Metals readily lose valence electrons to become positive ions and form ionic bonds with negative ions.
  • Non-metals (excluding the noble gases) can form either ionic bonds or covalent bonds.
  • When non-metals and metals combine, non-metals gain valence electrons to become negative ions and form ionic bonds.
  • When two non-metals combine, they share valence electrons to form covalent bonds.
  • Noble gases do not form bonds with other atoms because they already have full valence shells and are therefore very stable.

 
ionic covalent bonding sulfur metals non-metals

Sulfur can form ionic bonds with metals and covalent bonds with non-metals.

 

Bonding and the Periodic Table

  • Since the layout of the periodic table is related to the electron configurations of elements, the types of bonding and structures that atoms may form can be predicted from their location on the periodic table.
  • The periodic table can be divided into noble gases, other non-metals, metals and metalloids.
  • Noble gases are located in group 18.
  • None of these elements form chemical bonds (under most conditions).
  • Other non-metals are located in the upper sections of groups 14-17 (except for hydrogen, which is located at the top of group 1).
  • All of these elements form covalent bonds with themselves and other non-metals.
  • Most will also form ionic bonds with metals.
  • Metals are located in groups 1-12 and the lowers sections of groups 13-16.
  • All of these elements have metallic bonding and form ionic bonds with non-metals.
  • Metalloids are located in a diagonal band from the top of group 13 to the bottom of group 17.
  • Metalloids have intermediate properties of metals and non-metals.
  • These elements can usually form both ionic and covalent bonds.

 
periodic table chemical bonding

The types of bonding and structures that atoms may form can be predicted from their location on the periodic table.

 


Summary

  • Chemical bonds are strong forces of attraction between atoms that hold them together.
  • Atoms in elements and compounds can be joined by three different types of chemical bonds:
  • Metallic bonds
  • Electrostatic forces of attraction between positively charged metal ions and the negatively charged electrons surrounding them.
  • Ionic bonds
  • Electrostatic forces of attraction between positive and negative ions.
  • Covalent bonds
  • Bonds involving the sharing of valence electrons between non-metal atoms.
  • The different types of chemical bonds, or the lack thereof, result in five different types of chemical structures:
  • Monatomic structures
  • Individual atoms, with no chemical bonds between them.
  • Include elements only.
  • Metallic structures
  • Rigid but malleable lattices of metal ions surrounded by delocalised valence electrons, connected by metallic bonds.
  • Include elements and alloys.
  • Ionic structures
  • Hard lattices of positive and negative ions, connected by ionic bonds; composed of monatomic metal and non-metal ions, or polyatomic ions.
  • Include compounds only.
  • Covalent molecular structures
  • Discrete molecules consisting of non-metal atoms joined by covalent bonds.
  • Include elements and compounds.
  • Covalent network structures
  • Hard lattices of non-metal atoms connected by covalent bonds; may also involve metalloid atoms.
  • Include elements and compounds.

 
chemical bonding structures metallic ionic covalent

(Header image: AlexanderAlUS, Wikimedia Commons)

 

 chemical bonding and structures worksheet  year 10 chemistry pdf workbook  Year 10 Chemistry Print Workbook Australian Curriculum

Click images to preview the worksheet for this lesson and the Year 10 Chemistry Workbook (PDF and print versions)