Which of the following is not a property of persistent organic pollutants

What is the percentage by mass of silicon (si) in iron aluminum silicate (fe3al2(sio4)3)?

Uranium can supply energy for the worlds electricity without admitting harmful greenhouse gases which of these statements best describes an outcome of uranium mining

With the largest atoms and the smallest number of valence electrons and with the smallest atoms and the greatest number of valence electrons are the most reactive. a. nonmetals; metals b. nonmetals; transition elements c. transition elements; metals d. metals; nonmetals