<u>Answer:</u> When oppositely charged species interact.
<u>Explanation:</u>
Ionic compound is defined as the compound which is formed by the complete transfer of electrons from one element to another element.
In these compounds, oppositely charged ions are attracted towards each other to form a compound.
<u>For Example:</u> NaCl is formed by the attraction of 
ions. So, same number of oppositely charges maintain electrical neutrality.
Electrical neutrality in a compound is achieved when atoms forming a compound have same number of opposite charges. Basically the charges on cation is balanced by the charges on anion.
Compound are formed by two or more elements chemically combined. For example: H^2O is the water formula, this is a compound because you two elements which are Hydrogen and Oxygen and together they form a compound. The (^2) is the amount of atoms the formula has, in this case Hydrogen has two atoms and Oxygen is neutral.
Please don’t listen to those people who always put links those are scams. The answer is the kidney, ureters, bladder, and urethra. This system filters your blood,removing waste and excess water. Your welcome!
T cells and B cells are similar because they both deal with fighting of viruses.
