bond energy

In chemistry, bond energy, also called the mean bond enthalpy or average bond enthalpy is the measure of bond strength in a chemical bond. 

IUPAC defines bond energy as the average value of the gas-phase Bond-dissociation energy for all bonds of the same type within the same chemical species. Wikipedia

activation energy

activation energy

noun

CHEMISTRY

the minimum quantity of energy which the reacting species must possess in order to undergo a specified reaction.

Britannica

2. Activation energy. chemistry. Activation energy, in chemistry, the minimum amount of energy that is required to activate atoms or molecules to a condition in which they can undergo a chemical transformation or physical transport.
3. Activation energies are determined from experimental rate constants or diffusion coefficients that are measured at different temperatures.
4. 
   
5. Many elements can form two or more covalent bonds, but only a few are able to form extended chains of covalent bonds. The outstanding example is carbon, which can form as many as four covalent bonds and can bond to itself indefinitely. Carbon has six electrons in total, two of which are paired in an atomic orbital closest to the nucleus. The remaining four are farther from the nucleus and are available for covalent bonding. When there is sufficient hydrogen present, carbon will react to form methane, CH4. When all four electron pairs occupy the four molecular orbitals of lowest …(100 of 16152 words)
7. 
   
8.