How do scientists determine the number of neutrons in an isotope of an atom?
o
they add the number of protons and electrons.
o
they subtract the number of protons and neutrons from the mass number
o
they subtract the number of protons from the mass number
o
they subtract the number of electrons from the mass number

Option (c) is the correct answer.

Explanation:

Isotopes are the species that contain same number of protons but different number of neutrons.

For example, isotopes of carbon are and .

So, both these atoms contain six protons but different number of neutrons.

As sum of total number of protons and neutrons present within an element is known as atomic mass.

Hence, number of neutrons can be calculated as follows.

                      Atomic mass = atomic number + no. of neutrons

                  No. of neutrons = atomic mass - atomic number

Thus, we can conclude that scientists determine the number of neutrons in an isotope of an atom as they subtract the number of protons from the mass number.

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).