How many atoms of aluminum are in one formula unit of aluminum chloride? one two three six

Asample of radium-226 will decay 1/4 of its original amount after 3200years. what is the half-life of radium-226?

What are the first two quantum numbers for the electrons located in subshell 4d? what are the first three quantum numbers for the electrons located in subshell 2s? how many electrons can be held in a sublevel l = 3? how many electrons can be held in the energy level n = 4? how many electrons in an atom can share the quantum numbers n = 4 and l = 3?

Word equation for k(s) +h2o(l) yield koh (aq) + h2