What is the arrangement of electron pairs of pbr3? predict the molecular shape of a pbr3 molecule?

When the earth was formed and cooled, why did nickel and iron end up in the center of the earth while basalt and granite ended up in the outer layers

What’s a special glass that most beakers are made of

What is the molar mass of the anhydrous compound? answer using four significant figures. 36.02 g/mol 120.15 g/mol 156.12 g/mol