The atom is stable when the outermost energy level of most atoms has eight electrons. Electrons can be transferred carrying energy to another molecule. H atom can carry electrons for transfering energy. Oxygen and nitrogen are electronegative, having strong affinities for electrons. Stability can be achieved by adding, losing, or sharing electrons.
Double bond means two pair of electrons are shared.
C. Sharing electrons leads to the formation of covalent bonds. 1 calorie is the heat needed to raise the temp. Bonding patterns of Biologically Important Elements. Structure is crucial for understanding biology. Two or more atoms are linked by a chemical bond is a molecule.