Are phosphorous and oxygen covalently or ionically bonded?

Why do sodium and neon have vastly different chemical and physical properties despite having similar atomic masses?

An experimental procedure requires a 10 ml of acid to be dissolved

The table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.