Covalent bonding

• Simple Covalent Molecules


  N N H O H Ar O C O
• Bonding so far

  1. Looked at atomic structure

  2. Looked at how ions are formed (Cations –Positive and Anions-Negative)

  3. Looked at drawing how metal ions and non-metal ions bond together in ionic bonding

  4. Looked at the properties of ionic bonding
• STARTER: Access Educake quiz tool, use your username and password to login, complete the quiz "Year 9- Ionic Bonding Starter" (10 questions)
• In Your Workbooks: Write the date, Write the title "Drawing simple covalent bonding", Complete the tasks on the following slides
• Lesson Objectives

  • Recall how covalent bonds are formed
  • Show how covalent bonds can be represented
  • Understand what types of substances contain covalent bonds
  • Explain the properties of covalent compounds
• Cartoon Interpretation: How does covalent bonding differ from ionic bonding? Give examples to support your answer. Look at the cartoon image. Write What are the features of covalent bonding ? (work it out from the image- 1 is done for you in red)
• Features of covalent bonding

  • Covalent bonding only happens with non metals
  • Covalent bonding involves sharing electrons
  • "Spreads happiness"- means atoms are bonding to get a full outer shell
  • Covalent bonding does NOT involve metal atoms
• Atoms of non metals


  Tend to gain electrons to achieve stability. When they react with each other neither can give away electrons so they share electrons. These bonds are strong.
• Covalent Bonding

  When 2 or more non-metal atoms share electrons to form a bond and gain a full outer shell of electrons (stability)
• Covalent Bonding ONLY occurs between non-metals (highlighted in yellow)
• How to draw molecules that are covalently bonded

  It's easiest to draw one of them with a dot and one as a cross (to show where electrons are coming from)
• EXAMPLE 1: Drawing Covalent molecule HYDROGEN (H2)


  • Draw the electron structure of 2 hydrogen atoms side by side
  • Each hydrogen atom needs one more electron in its outer shell (full shell =2) and so each atom shares its single unpaired electron
  • This shared pair of electrons forms a SINGLE covalent bond and so creates a diatomic molecule of hydrogen
• Covalent bonding in hydrogen

  Only outer shells of electrons are involved in bonding. Two common ways to represent a covalent bond are: Structural formula diagram – 1 solid line for each electron pair shared, simplified dot and cross diagram (only show the outer shell of electrons)
• Class Task: Practice drawing dot and cross and structural diagrams for 1-4


  1. Use the video guidance "How to draw covalent molecules"

  2. You only need to draw the outer shell of electrons

  3. The group number tells you how many electrons are in the outer shell
• Hydrochloric Acid (HCl)


  • Draw one atom of Chlorine and one atom of Hydrogen showing their outer electrons only. How could these bond together to form a full outer shell each?
• Methane (CH4)


  • Draw one atom of Carbon and four atoms of Hydrogen showing their outer electrons only. How could these bond together to form a full outer shell each?
• Oxygen (O2)


  • Draw two atoms of oxygen showing their outer electrons only. How could these bond together to form a full outer shell each?
• Nitrogen (N2)


  • Draw two atoms of Nitrogen showing their outer electrons only. How could these bond together to form a full outer shell each?
• Main Task (Drawing Covalent Bonds)

  Use the grid provided, reference the class examples, use your textbooks, and use your periodic tables
• EXTENSION: Summary Questions
• Covalent bond

  Two electrons are in each bond
• Elements that form covalent bonds


  Only non-metals form covalent, as they both want to gain electrons, so instead share electrons
• Where electrons in a covalent bond come from

  Electrons come from the outer most shell of electrons in an atom
• Number of covalent bonds formed by elements

  • Carbon- 4, Nitrogen-3, Chlorine- 1, Oxygen-2
• Evaluate using the dot and cross diagrams and 2D structural diagrams to represent covalent bonding. (Advantages and Disadvantages)