3. Covalent bonding

Available for over a year

In this episode, Dr Sunayana Bhargava and Tulela Pea define covalent bonding and look at the properties of molecular compounds. Suitable for: AQA, Edexcel, OCR. For more information on covalent bonding, check out the BBC Bitesize website: https://www.bbc.co.uk/bitesize/guides/z373h39/revision/1 Key learning objectives discussed in this episode include: - When atoms share pairs of electrons, they form covalent bonds. These bonds between atoms are strong. - Covalent bonding occurs in most non-metallic elements and in compounds of non-metals. - Covalently bonded substances may consist of small molecules. - Students should be able to draw dot and cross diagrams for the molecules of hydrogen, chlorine, oxygen, nitrogen, hydrogen chloride, water, ammonia and methane. - Substances that consist of small molecules are usually gases or liquids that have relatively low melting points and boiling points. - These substances have only weak forces between the molecules (intermolecular forces). It is these intermolecular forces that are overcome, not the covalent bonds, when the substance melts or boils. - The intermolecular forces increase with the size of the molecules, so larger molecules have higher melting and boiling points. - These substances do not conduct electricity because the molecules do not have an overall electric charge.