Help pls 15 points The valence of an atom is determined by the nucleus.

True or False

Three alkali metals in group 1 are a. calcium, strontium, barium b. boron, aluminum, gallium c. sodium, potassium, rubidium d. fluorine, iodine, chlorine

Diffraction is when light is bent around obstructions. which of the these observation about clouds would indicate diffraction? a) after rain storms, you can sometimes see rainbows. b) clouds are white or gray and cannot be seen through. c) on a cloudy day, the temperature tends to be cooler than a sunny day. d) the edges of dark clouds appear lighter. this

Use the periodic table to find the molar mass of each element. molar mass h = g/mol molar mass s = g/mol molar mass o = g/mol