An element has two naturally occurring Isotopes. The mass numbers of these isotopes are 109.00 u and 111.00 u, with natural
abundances of 20% and 80%, respectively. Calculate its average atomic mass, Report your answer to 2 decimal places.

When you mate two plants together the terms is called? answer it fast as possible plz! i have a test tomorrow!

When a spring is compressed, the energy changes from kinetic to potential. which best describes what is causing this change?

Three cards with holes are arranged in a straight line. a light is shined through the first card’s hole and travels through all three cards. what does this tell you about light rays? a) that light is reflected b) that light is refractive c) that light travels in a straight line d) that light does not travel in a straight line