covalent bonding Flashcards
What do non-metal atoms do to form covalent bonds?
Share electrons to obtain a full outer shell of electrons.
What are covalent bonds formed by?
Pairs of shared electrons.
What are bonding electrons?
Electrons that are shared in a covalent bond.
What are non-bonding electrons?
Electrons on the outer shell not involved in covalent bonds.
How are covalent bonds represented?
By a short straight line between the two atoms.
True or False: In covalent bonds, electrons are transferred between atoms.
False.
What type of structures can covalently bonded substances form?
- Simple molecular structures
- Giant covalent structures.
Give two examples of simple molecular structures.
- Oxygen (O2)
- Water (H2O).
Give two examples of giant covalent structures.
- Diamond
- Graphite.
What are intermolecular forces in simple molecular structures?
Weak forces acting between neighboring molecules.
Why do simple molecular structures have low melting and boiling points?
Weak intermolecular forces require little energy to overcome.
What is C60 fullerene?
A group of carbon allotropes forming hollow tubes or spheres.
What is the first fullerene discovered?
Buckminsterfullerene, also known as a ‘buckyball’.
What is the structure of buckminsterfullerene?
60 carbon atoms forming 20 hexagons and 12 pentagons.
True or False: C60 can conduct electricity.
False.
What happens as the relative molecular mass of a substance increases?
Melting and boiling points generally increase.
What makes simple molecular structures poor conductors of electricity?
No free ions or electrons to move and carry the charge.
What are giant covalent structures also known as?
Giant lattices or macromolecules.
What is the bonding structure in diamond?
Each carbon atom bonds with four other carbons, forming a tetrahedron.
What makes diamond very hard?
Strong covalent bonds between carbon atoms.
How many covalent bonds does each carbon atom in graphite form?
Three.
What property of graphite allows it to conduct electricity?
Delocalised electrons that are free to move.
Why is graphite soft and slippery?
Layers of carbon atoms are free to slide over each other due to weak forces.
Explain the melting point of giant covalent structures.
They have many strong covalent bonds that require lots of energy to break.
difference of diamond and graphite (6)
M1 diamond has a tetrahedral (structure) OR in
diamond each (carbon) atom is (covalently) bonded to
4 other (carbon) atoms
M2 graphite has a hexagonal (structure) / has layers
OR in graphite each (carbon) atom is (covalently)
bonded to 3 other (carbon) atoms
M3 diamond does not conduct electricity OR graphite
conducts electricity
M4 diamond has no delocalised electrons OR graphite
has delocalised electrons
M5 diamond is hard OR graphite is soft
M6 in diamond the strong (C-C) bonds need to be
broken OR in graphite the layers can slide over each
other OR graphite has weak forces between layers
