There are 115 known elements as of today (Feb. 13, 2016)
so, 'C' is the correct answer
<span>The third equivalence point is not observed in the titration curve of phosphoric acid because the specific point is concealed due to the rapid ionization of water which in turn forms an hydroxide ion and a molecule called hydronium molecule. The pH value changes more at the first and second points.</span>
The answer would be B) Lower, because pure water freezes at 32 degrees Fahrenheit whereas salt water freezes at 28.4 degrees Fahrenheit. Hopefully this helps!
The method of determining the most common isotope of lead is by determining the average atomic mass. The formula for determining the average atomic mass is:

Substituting the values in the formula:



The most common isotope of lead is:
Lead - 207.22 amu
The atomic symbol of lead is
. The atomic number of
is 82.
So, the the most common isotope of lead can be written as:
and Lead - 207.22 amu.