Covalent Bonding Flashcards
What is covalent bonding?
The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms. Occurs between non metals and polyatomic ions.
What happens in the covalent bond?
Atomic orbitals overlap, each containing 1 electron to give a shared pair of electrons. The shared pair of electrons is attracted to the nuclei of both bonding atoms.
Which direction does the attraction in a covalent bond go compared to in an ionic bond?
A covalent bond is localised, acting solely between the shared pair of electrons and nuclei of the bonded atoms. Results in a molecule
An ionic bond attracts oppositely charged ions in all directions, resulting in a giant ionic lattice
How to draw dot and cross diagrams in covalent bonding?
Draw out the atoms, overlap the electron shell circles
Draw dots and crosses and other shapes if necassery and pair them together. Can also draw a displayed formula.
All electrons must be drawn.
What is a lone pair?
A pair of electrons that are not shared.
How many covalent bonds does carbon make?
4
How many covalent bonds does nitrogen makes?
3
How many covalent bonds does oxygen make?
2
How many covalent bonds does hydrogen make?
1
How does boron bond?
Only has 3 outer shell electrons.
Can only bond with 3 others
Shape predictions can only be based on noble gas electron structure.
How does phosphorus, sulphur and chlorine bond?
N=2 can only hold 8 electrons
N=3 can hold 18 electrons so more electrons are available for bonding
Expansion of the octet, only possible from N=3 as the d sub shell becomes available for expansion
What is a dative covalent bond?
A covalent bond in which the shared pair of electrons has been supplied by one of the bonding atoms only. Shared electron pair was originally a lone pair.
What is the relationship between average bond enthalpy and covalent bond strength?
The larger the value of the average bond enthalpy, the stronger the covalent bond.
