A certain element XX has four isotopes. 4.350% of XX has a mass of 49.94605 amuamu . 83.79% of XX has a mass of 51.94051 amuamu . 9.500% of XX has a mass of 52.94065 amuamu . 2.360% of XX has a mass of 53.93888 amuamu . What is the average atomic mass of element XX

Express the following number in scientific notation. 0.026890 =

Choose all the answers that apply. ionic compounds dissolve easily in water do not dissolve in water have low melting points have high melting points conduct electricity when melted

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