Answer:
An acid is a substance or compound that releases hydrogen ions (H+) when in solution. In a strong acid, such as hydrochloric acid (HCl), all hydrogen ions (H+), and chloride ions (Cl-) dissociate (separate) when placed in water and these ions are no longer held together by ionic bonding.
I think you are refering to the periodic table. The periodic table is important because it is organized to provide a great deal of information about elements and how they relate to one another in one easy-to-use reference. The table can be used to predict the properties of elements, even those that have not yet been discovered.
The basic repeating unit of nucleic acids are known as nucleotides
