Molecular Models
Atoms form bonds to become molecules and compounds because of their electrons. Today
we will be modelling covalent bonds which occur when electrons are shared between atoms.
Complete the following table.
Element
Oxygen
Electron configuration
(written and diagram)
Number of extra electrons
the atoms needs to gain
(ionic bonding) or share
(covalent bonding)
2.6
Carbon
Hydrogen
Nitrogen
Examine the atoms that represent oxygen, carbon, hydrogen and nitrogen.
What do the holes in the balls represent?
Atoms stay in molecules because once they are in these, they have full outer electron shells,
and are thus stable. This means that for a stable compound to be formed, the entire valence
(outer) electron shell must have been filled (no holes left unfilled in the molecular models).
Make and draw the following compounds, and express their structural formula.
Chlorine Cl2
Oxygen O2
Nitrogen N2
Carbon dioxide CO2
Methanal CH2O
Ethanol CH3COOH (Hints: one of the oxygen atoms is joined only to a single carbon atom).