3.2 Covalent bonding Flashcards
Covalent bond:
The sharing of valence electrons to form a stable arrangement
In between what molecules do covalent bondings form?
Non-metals
How do sharing electrons hold together?
With electrostatic forces of attraction between the +ve nuclei and the -ve shared electrons
What are double covalent bonds?
Four electrons shared
Melting points of molecular structures with covalent bonds
Low melting points
Poor conductors of electricity
Why do molecular structures with covalent bonds have low melting points and are poor conductors?
-covalent bonds are only between atoms and not molecules
-no charged particles that can flow and carry charge
What are dative covalent bonds?
When one of the atoms in a covalent bond is the one sharing the shared electrons
Draw NH4+
NH3
Dative bond to H+
How are coordinate covalent bonds represented?
With arrows
The arrow points to the atom accepting the e- pair
Why does diamond have a high melting point?
- Each C atom is bonded to 4 other C atms
- in a giant covalent structure
- lots of energy needed to overcome the covalent bonds
Why can graphite conduct electricity but diamond can’t?
- graphite is bonded to 3 C atoms, has delocalised e-
- free to move and carry charge through the structure
- diamond doesn’t have any
