An element has three stable isotopes with masses of 68.217 amu, 69.226 amu, and 70.235 amu. The heavier two isotopes have an abundance of 44.99% and 42.96%, respectively. What is the mass of the element?

1)Write the isotopic symbol of niobium with 64 neutrons using the form X-A (e.g., He-5).

2) What ion is represented by the following information?

p+	=	71
n0	=	170
e-	=	72

3) Use the "Edit Answer" button to type in your formula. Ionic charges are superscripts composed of a number followed by a sign (i.e. '^2+').

4)Select all the statements below that are true. A. Solids are always denser than liquids. B.Solids do not change shape to fill a container. C.All solid substances do not have long-range repeating order. D.Solids can never be mixtures. E. Liquid substances do not have long-range repeating order. F. Gases are highly compressible.