Chemical bonding Flashcards
Why do ionic compounds have a high melting and boiling point?
In ionic compounds, the cations and anions are arranged in an orderly, alternating manner. This forms a giant ionic lattice structure. Ionic bonds have strong electrostatic forces of attraction between the cations and anions in the lattice.
Why are ionic compounds unable to conduct electricity in solid form, but able to in molten or aqueous form?
In solid state, the cations and anions are not able to move about as they are held in position by the giant ionic lattice.
However, in molten/aqueous state, the giant ionic lattice is broken down. The cations and anions can move about freely and conduct electricity.
Why do covalent compounds have a low melting and boiling point?
Covalent molecules have weak intermolecular forces of attraction.
Why are covalent molecules unable to conduct electricity in any state?
Absence of mobile carriers, e.g. cations, anions or free electrons.
What are allotropes?
Allotropes are different physical forms of the same element.
What is a diamond’s structure and bonding like?
Diamond is made up of a large number of carbon atoms bonded covalently. Each carbon atom forms a covalent bond with 4 other carbon atoms.
What is another giant molecular structure that has a similar structure as diamond?
Silicon dioxide.
What is graphite’s structure and bonding like?
Graphite is made up of many flat layers of hexagonal rings formed by carbon atoms. Each layer is a giant molecule consisting of strong covalent bonds. The layers are held together by weak Van der Waals forces of attraction. Each carbon atom is covalently bonded with only 3 other carbon atoms. The last electron is delocalised.
