He definition "'oxygen' means an element having an atomic weight of 8 and an atomic number of 16" is an example of:

Answer is: a theoretical definition. But this definition is wrong because oxygen has atomic number 8 and atomic weight 16.
Theoretical chemistry is part of chemistry which develops theoretical generalization. For example, atoms atomic and mass weight, chemical bonding, chemical reaction, potential energy, molecular orbitals.

Ithe undersigned only for use your own email and delete any and copies and of the itself and to be there is a good timewhat does a decrease in temperature indicate about the molecules in a sample of liquid water? decreased chemical energy of the moleculesdecreased kinetic energy of the moleculesincreased chemical energy of the moleculesincreased kinetic energy of the moleculeshow does a sample of helium at 15 â°c compare to a sample of helium at 215 k? the helium at 15 â°c has a higher average kinetic energy than the sample at 215 k.the helium at 15 â°c has lower nuclear energy than the sample at 215 k.the helium at 15 â°c has slower-moving atoms than the sample at 215 k.the helium at 15 â°c has smaller atoms than the sample at 215 k.