The isotope of an unknown element, x, has a mass number of 79. the most stable ion of the isotope has 36 electrons and forms a binary compound with sodium having a formula of na2x. which of the following statements is(are) true? for the false statements, correct them. a. the binary compound formed between x and fluorine will be a covalent compound. b. the isotope of x contains 38 protons. c. the isotope of x contains 41 neutrons. d. the identity of x is strontium, sr.