What is the half-life of an isotope if after 2.00 weeks you have 31.25 g remaining from a 250.0 g starting sample size

What is the molar mass of babr2? a. 217.2 g/mol b. 297.1 g/mol c. 354.5 g/mol d. 434.4 g/mol

Which class of molecules functions as chemical signals? hormones water carbohydrates proteins

Select all of the statements which are true. electrons are located in shells or orbits around the atom. electrons orbit slowly around the atom. electrons travel in one flat path around the nucleus of an atom. the valence of an atom is determined by the number of electrons in the atom's outermost shell.