The half-life of radioactive element krypton-91 is 10 seconds. if 16 grams of krypton-91 are initially present, how many grams are present after 10 seconds? after 50 seconds?

Can someone me with 1 to 4 plz. fast

An atom of lithium (li) and an atom of chlorine (cl) engage in a chemical reaction. which correctly describes the structure of the resulting chemical compound? hint: consider the class of each element. the chemical compound will have a network structure. the chemical compound will have triple bonds. the chemical compound will have a ball-and-stick structure. the chemical compound will have double bonds.

13. a covalent bond between two atoms is likely to be polar if: a. one of the atoms is much more electronegative than the other. b. the two atoms are equally electronegative. c. the two atoms are of the same element. d. the bond is part of a tetrahedrally shaped molecule. e. one atom is an anion.