Topic 4: Bonding and Structure Flashcards
Define covalent network solid
One in which the atoms are held together by covalent bonds in a giant three-dimensional lattice structure.
What are some examples of giant network solids?
Diamond, graphite, graphene, and Silicon Dioxide. FULLERENE IS MOLECULAR NOT GIANT COVALENT
What are the properties of covalent network solids?
High melting points (carbon is highest, then graphite, then graphene); poor electrical conductivity (except graphite and graphene b/c of delocalized electrons); typically insoluble. generally hard, although in graphite the layers can slide past each other.
What are the properties of C60 fullerene?
Soluble in non-polar solvents; low melting/boiling point;
State three physical properties associated with metals and explain them at the atomic level.
High electrical/thermal conductivity –> in metallic bonding, the delocalized electrons can move around freely, so they can carry an electrical charge and conduct electricity. Malleability –> the attraction is for the electrons rather than the ions, therefore they can be moved with pressure without disrupting the bonding. Shiny –> The electrons can absorb light at different wavelengths making them shiny in appearance.
How can ozone be created in the troposphere?
NOx + Volatile Organic Compounds + UV radiation (sunlight) –> O3
What is the significance of O3 in the troposphere?
It can cause respiratory problems such as asthma and emphysema as well as produce photochemical smog.
Outline the principles of VSEPR theory.
Find the number of charge centers in the central atom; charge centers of central atom repel each other(;) to positions of maximum stability; pairs forming a double or triple bond act as a single bond; non-bonding pairs repel more than bonding pairs
What are the properties of SiO2?
High melting and boiling points (b/c strong covalent bonds); insoluble in water; solid cannot conduct electricity, but molten can because electrons are free to move.
Define metallic bond.
A metallic bond is an electrostatic attraction between a lattice of positive ions and delocalized electrons (from low ionization energies).
What factors influence the strength of a metallic bond?
Number of valence electrons (that can become delozalized); the charge of the metal ion (more attraction to the electrons); the ionic radius of the ion (the more shells, & therefore larger radius, the more shielding will occur weakening the bond).
