on the periodic table, elements are arranged by which of the following. A. mass numbers. B. increasing atomic number. C. alphabetical order. or D. density

7. A solution contains a mixture of pentane and hexane at room temperature. The solution has a vapor pressure of 250 torr. Pure pentane and hexane have vapor pressures of 425 torr and 151 torr, respectively, at room temperature.

A compound with formula AL (XF4) 3 contains (unidentified) element X, which is 11.3% by mass of the composition of the substance. What is identity of element X

If two atoms combine by sharing electrons, what kind of bond is formed?

When a sulfur atom gains its valence electrons to have 8, the charge on the resulting ion is

An inert electrode is a substance that is: A) Sacrificed B) Degraded C) Present in the salt bridge D) none of the above

Which of the following is true concerning the noble gases? A. Their highest occupied s and p sublevels are filled. B. They belong to Group 8A. C. They are sometimes referred to as the inert gases. D. all of the above

Which of the following is responsible for passing albinism from a parent organism to its offspring?

Rubidium has two naturally occurring isotopes, rubidium - 85 (atomic mass = 84.9118 amu; abundance = 72.15%) and rubidium - 87 (atomic mass = 86.9092; abundance = 27.85%). Calculate the atomic weight of rubidium

You are asked to analyze an aqueous solution (X) and determine what's in it. You pour some of your sample X into a test tube and add a few drops of an acid. No observable reaction occurs.

Which of the following items represents a chemical change? burning melting evaporation freezing