What is a property of the Noble Gases? * A. They are not reactive because their outer valence electron shell is full.
B They are very reactive
C. They can be found in the atmosphere
D. They react readily with oxygen in the atmosphere

A. They are not reactive because their outer valence electron shell is full.

Explanation:

Noble gases are group 18 elements which are Helium , Neon , Argon , Krypton , Xenon and radon.

Noble gases have general electronic configuration of

As the sub-shells of noble gases is fully filled and their octet is complete. Hence, it will not gain or lose any electron and thus is non reactive in nature.

They do not react with other elements under ordinary conditions.

Thus the correct statement is they are not reactive because their outer valence electron shell is full.

most historians agree that gabriel mouton, the vicar of st. paul’s church in lyons, france, is the “founding father” of the metric system. he proposed a decimal system of measurement in 1670. mouton based it on the length of one minute of arc of a great circle of the earth (now called a nautical mile, 1852 meters). he also proposed the swing-length of a pendulum with a frequency of one beat per second as the unit of length (about 25 cm). a pendulum beating with this length would have been fairly easy to produce, thus facilitating the widespread distribution of uniform standards. over the years, his work was revised, improved, and extended by a number of french scientists.

the political sponsor of weights and measures reform in the french revolutionary national assembly was the bishop of autun, better known as talleyrand. under his auspices, the french academy appointed several committees to carry out the work of developing a usable system of weights and measures for france. one of the committees recommended a decimalized measurement system based upon a length equal to one ten-millionth of the length of a quadrant of the earth’s meridian (i.e., one ten-millionth of the distance between the equator and the north pole).