Atoms of chemical elements having same atomic mass but a different atomic number are called Isobars. The sum of the number of protons and neutrons together form the atomic mass. Therefore, we can also say the number of nucleons present in the nucleus is equal to the atomic mass of an atom. It will have the same number of nucleons. The number of protons and neutrons alone will vary but the number of nucleons or the sum of protons and neutrons in isobars will always be same. Isobars always have different atomic structure because of the difference in atomic numbers. The number of neutrons makes up the difference in the number of nucleons. Therefore, they are always different chemical elements having same atomic masses. Thus, isobar has different chemical properties. For example : Iron and nickel have atomic number 26 and 28 respectively. However, the mass number is 58. Argon and calcium with atomic number 18 and 20, respectively. However, they have the same atomic mass 40.
A neutralization reaction is when an acid and a base react to form water and a salt and involves the combination of H+ ions and OH- ions to generate water. The neutralization of a strong acid and strong base has a pH equal to 7. For example when HCl (Hydrochloric acid), a strong acid, reacts with NaOH, a strong base, the resulting salt is sodium chloride and water.