What type of elements from ionic compounds?
how are the ions held together in an ionic bond?

Ionic compounds are formed from the chemical bonding of metals with nonmetals or the combination of metals with polyatomic ions. These compounds consists of electrically charged particles known as ions, which occur when neutral atoms or molecules either gain or lose electrons. Some examples of ionic compounds are ferrous hydroxide, chromium phosphate and mercury(I) chloride.

Explanation:

if two electrons have the same n, the same ℓ, and the same ml, then they are in the same orbital. the pauli exclusion principle states that no two identical fermions (a fancy word for electrons and other subatomic particles like electrons) may occupy the same quantum state in an atom simultaneously.

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