Chapter 3 - Structure and Bonding Flashcards
What is ionic bonding between?
Metals and non-metals that are positively charged ions. Elements in group 1, 2, 6 and 7 can form ionic compounds.
What is covalent bonding
When atoms of non-metallic elements join together by sharing electrons.
Giant ionic structures
Giant structures with many strong electrostatic forces (ionic bonds). Lots of energy needed to overcome the bonds and melt the solid - high melting and boiling point.
Ionic substances can
Conduct electricity when molten or dissolved in water because the ions are free to move so can carry charge.
Covalent bonds join
Atoms to form molecules.
Simple molecules
Substances made up of simple molecules have low melting and boiling points, weak intermolecular forces. Have no charge so cannot carry electrical charge.
Giant covalent structures
Atoms joined together by strong covalent bonds, have very high melting points.
Diamond
A form of carbon with a regular 3-D structure. Every carbon atom is covalently bonded to four other carbon atoms making it hard and transparent. Very high melting points.
Graphite
A form of carbon in which each atom is covalently bonded to three other carbon atoms in giant flat 2-D layers. No covalent bonds between layers (weak intermolecular forces) so can slide over each other. One electron from each carbon atom is delocalised, allowing graphite to conduct heat and electricity.
Fullerenes
Large molecules formed from hexagonal rings of carbon atoms, join to form cage-like shapes with different numbers of carbon atoms.
Nanoscience
Study of small particles between 1 and 100 nanometres in size.
Nanoparticles
Large surface area. Used as catalysts, new coatings, new cosmetics such as deodorants and highly selective sensors.
Nanocages
Can carry drugs inside them and nanotubes can reinforce materials.
