Answer:
1. Sodium (Na) is the most reactive due to its lower number of shells which enables the protons in it's nucleus to attract more electrons.
2. Calcium (Ca) is next as it is a group 2 element and they can be quite reactive.
3. Zinc (Zn) is the third reactive as transition metals are not very reactive.
4. Copper (Cu) is less reactive than Zinc because it is closer to the center of the periodic table and therefore has more stability.
5. Gold (Au) is the least reactive.