Astatine is the rarest naturally occurring element in the Earth's crust. If only about 1.00x1023 atoms of astatine exist at any one time on Earth then what mass in kilograms is that
equivalent to?

The modern periodic table has groups.

The characteristic of two different types of reactions are shown below. reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of and element. which statement is true about the atoms of the elements that participate in the two reactions? a: their identity changes in both reaction a and b. b: their identity changes in reaction a but not b. c: their identity changes in reaction b but not a. d: their identity remains the same.

Is a pencil falling to the floor anon contact force, a force, or a contact force