What is the standard for comparison for the relative masses listed n the periodic table?

Answer 1

The standard comparison for atomic weights on the Periodic Table is carbon 12. This is a common isotope of carbon which has 6 protons and 6 neutrons. Carbon 12 is assigned an Atomic Mass of 12, and other elements' atomic masses are all relative to this value.

Answer 2

The relative atomic mass of an atom is a comparison of the mass of that element with a certain reference(i.e 1/12 of the mass of a carbon-12 atom),and hence the word relative.For eg. When i say the relative atomic mass of oxygen atom is 18 (notice no units),that implies it is 18 times heavier than 1/12 of the mass of a carbon -12 atom.There are no units because we are taking the ratio,i.e relative to each other,so the unit cancells out.

It is required to relate masses from the atomic world which are of extremely small order(say 10^-34!!) to our world(in normal grams or kgs)

Also the mass of 1/12 of a carbon 12 atom was chosen because it gave simpler whole number ratios when divided with the mass of other atoms.The mass of a 1/12 of a carbon 12 atom was measured by a spectroscope,and it equals 1.6605×10^−27 kg.

Answer 3

It is possible to compare the mass of one element to other elements, based on the average mass of the existing isotopes as found in nature, or, to compare the mass of one isotope to another isotope. For example, the lightest and most common isotope of hydrogen, which we can call hydrogen one (which has one proton in its nucleus and no neutrons), weighs only one quarter as much as the most usual isotope of helium, helium four (which has two protons and two neutrons in its nucleus). To get the atomic weight of an element, based on average isotopic weights, you need only consult the periodic table of elements.

Answer 4

The standard for comparison for the relative masses listed in the periodic table is the carbon-12 isotope. The relative atomic mass values provided on the periodic table are based on the average atomic masses of the elements compared to one-twelfth the mass of a carbon-12 atom.

Answer 5

It is in the top right corner of the box the chemical symbol is in. it means that it is the mass of the chemical in grams.

Answer 6

If you mean 'What does Mass number mean on the periodic table?' Mass number shows how many Protons and Neutrons are in the Atom.

Answer 7

The amount of protons in an element.

Answer 8

to

Answer 9

atom