Arrange these species into isoelectronic groups. It does not matter which group goes in which box, so long as the correct species are grouped?

He, Li+, Al3+, Y3+, N3-, O2-, Br-, Be2+, Sr2+

The reaction q+r2=r2q is found to be first order in r2 and

What must happen before a body cell can begin mitotic cell division

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.