C3. Bonding Flashcards
What effect do lone pairs have on bond angles?
Greater repulsion than bonding pairs, lone pairs have 2.5 degree effect on bond angles
What are the different types of bonding?
Ionic, Covalent, Metallic
What is ionic bonding?
Electrostatic attraction between positive and negative ions in a lattice
What substances can an ionic bond exist between?
Metal - non metal ions; hydrogen - non metal ions
What are the properties of ionic compounds?
Crystalline solids, high melting and boiling points, soluble in water, conduct electricity as molten or aq, hard and brittle
Why do ionic structure have high melting and boiling points?
Large amount of energy required to overcome large number of strong electrostatic forces between ions in lattice
Why are ionic substances soluble in water?
+ and - dipoles in water are attracted to ions and pull lattice apart, energy is required (endothermic)
Why are ionic compounds hard and brittle?
Strong electrostatic forces holding lattice together, when struck, ions with like charge align and repel
What is a covalent bond?
Shared pair of electrons which are attracted to the nuclei in each atom
What substances can a covalent bond exist between?
Non metal atoms
What is a discrete covalent bond?
Small group of atoms held by strong covalent bond and weak intermolecular forces
What is a giant covalent bond?
3D structure held together by covalent bonds
What are the general properties of covalent bond?
Low melting and boiling points, no electrical conductivity, insoluble in water
What is a dative covalent bond?
Covalent bond where both electrons come from same atom
How do you show a dative covalent bond in a diagram?
Arrow point from donating atom to receiving atom
What is metallic bonding?
Valence electrons can move from one atom to another creating a cloud of delocalized electrons. The positive metal ions are immersed in this cloud. Electrostatic interactions are responsible for the metallic bond.
Metallic bonding joins a bulk of metal atoms
What are the physical properties of metals?
High density, high melting and boiling point, electrical conductivity, thermal conductivity, malleable, ductile
Why do metals have high melting and boiling points?
Many strong electrostatic forces hold lattice together, lots of energy required to overcome
Why can metals conduct electricity?
Delocalised electrons move randomly through lattice of positive ions, potential difference connected, carrying charge
Why do metals conduct heat?
Electrons bump into ions in cooler regions to transfer energy, vibration of tightly packed metal ions