Understanding atomic numbers and mass numbers is really important for learning about chemical reactions!

1. What Are They?

   • The atomic number (Z) tells us how many protons are in the nucleus of an atom. This number helps us know what element it is. For example, Carbon has an atomic number of 6.
   • The mass number (A) is the total of protons and neutrons in an atom. For example, Carbon-12 has a mass number of 12.

2. What Are Isotopes?

   • Isotopes are different forms of the same element. They have the same number of protons but different numbers of neutrons. For instance, Carbon-12 and Carbon-14 are both isotopes of Carbon but have different mass numbers.

3. How They Affect Reactions:

   • The atomic number helps decide how reactive an element is and where it fits on the periodic table. The mass number plays a role in how stable an atom is and its nuclear traits.
   • For example, Carbon-14 is special because it can be used to date old plants and animals. This is because it can break down over time in a process called radioactive decay.

By knowing about atomic and mass numbers, we can better understand how different substances react and create new ones.