Which of the following undergoes change during a chemical reaction? atomic masses of elements in reactants
element identities of atoms in reactants
total number of electrons in reactants
chemical bonds between atoms in reactants

In this item we are to determine which among the presented choices will undergo change during the chemical reaction. The answer is the chemical bonds between the atoms in the reactants. Depending on the nature of the reactants, different types of chemical bonds will be developed between the participating atoms.

I’m going to go with b!