0
This is a great question. Actually before 1961 12C had a different mass than it has today. The mass scale we use is actually relative and before 1961 the mass scale was based on Oxygen so 16O = 16 which was the standard in place since 1906. In the 20's people started to discover oxygen isotopes and the chemists 16O scale was not the same as the physicists 16O scale , so it was decided to settle on Carbon to make both the physicists and chemists happy
Check the related link below for the complete history of what happened
What else can I help you with?
Do all isotopes have whole number atomic masses?
The short answer is yes. The long answer is that isotopes have different numbers of neutrons than other isotopes of the same element, so when expressing the mass of an isotope, you don't take an average; you just add the number of neutrons and the number of protons. However, that number is not entirely accurate since the mass of a proton and a neutron are very slightly different. So, if you want to be very exact, then no, the mass of an isotope is not a whole number, but it is very, very close.
How do isotopes differ and why is the atomic number of elements not a whole number?
Isotopes differ from each other by having different numbers of neutrons but the same number of protons since they are only the same element if they have the same number of protons. Atomic numbers aren't whole because their mass is based of the mass of hydrogen and amu's (atomic mass units) and due to how elements are formed, minute amounts of mass are lost in order to form the nuclear bonds resulting in not whole numbers.
Why are molar masses not a whole number?
Molar masses are not whole numbers because they are calculated based on the average mass of isotopes present in a sample, taking into account the abundance of each isotope. Isotopes are elements with the same number of protons but different numbers of neutrons, leading to fractional atomic masses and consequently non-whole molar masses.
Why is Tc on the periodic table bracketed and a whole number?
Tc, technetium, is bracketed on the periodic table because it is a synthetic element and not found naturally on Earth. The whole number represents its most stable isotope, which is artificially produced in nuclear reactors or particle accelerators.
How do you find the atomic number of atoms?
Look it up in "Periodic Table of elements" You can find the number of a particular element by looking at the Periodic Table; you can also do this by counting the number of protons in the nucleus.
Why elements don't have whole numbers?
do you mean the why is the average atomic mass not a whole number? because if that is your question, then the answer is that each element has multipal isotopes and the mass you see on the periodic table is the average of all the isotopes together. So there has to be a decimal on the periodic table of elements
Why the mass numbers on the periodic table of elements are rarely whole numbers?
Elements also possess isotopes. So their average atomic mass is rarely whole number.
How were the positions of isotopes resolved in modern periodic table?
The positions of isotopes in the modern periodic table are not explicitly shown; instead, elements are represented as whole entities, with isotopes being variations of these elements based on their neutron count. The periodic table is organized by atomic number, which corresponds to the number of protons in an element's nucleus. Isotopes of an element share the same atomic number but have different atomic masses due to varying numbers of neutrons. The average atomic mass listed on the table reflects the weighted average of all naturally occurring isotopes of an element.
What is an element's atomic mass not listed as a whole number on the periodic table?
Few elements have isotopes. their atomic mass is not a whole number.
Why don't the elements on the periodic table have a whole number as their atomic weight?
Elements exist as isotopes in nature. So their atomic weight is not a whole number.
Which statement best explains why most atomic masses on the periodric table are decimal numbers?
Most atomic masses on the periodic table are decimal numbers because they are weighted averages of the masses of all isotopes of an element, taking into account their relative abundance. Since isotopes have different masses, the atomic mass is typically not a whole number.
Why don27t elements in the periodic table have whole numbers for their atomic masses?
Because the masses of protons, neutrons and electrons are not whole numbers.
Why is the atomic mass of sulfur listed on the periodic table not a whole number?
The atomic mass listed on the periodic table is a weighted average of all the naturally occurring isotopes of sulfur. Since these isotopes have different masses and abundances, the atomic mass is typically a decimal value. It reflects the average mass of all sulfur atoms taking into account the different isotopes and their relative abundances.
Why is the atomc mass not a whole number?
The atomic mass listed on the periodic table is a weighted average of all the known isotopes of an element. Since isotopes have different masses based on the number of neutrons they contain, the average atomic mass is not a whole number. It accounts for the abundance of each isotope in nature.
Why the atomic mass numbers listed for elements on the Periodic Table are not whole numbers.?
Why are atomic masses of elements not generally whole numbers? The atomic masses listed on the periodic table are a weighted AVERAGE of an element'sisotopes. ... An element's atomic number is the number of protons in its nucleus. Number of protons specifies atom type.
What number is the whole number found in the periodic table?
There are two numbers that are included in every element's block on every periodic table. The whole number, which can range from 1 - 118 is the atomic number of that element. The atomic number is the number of protons in the nuclei of the atoms of that element. The second number is the atomic weight and is never a whole number, except for the artificially prepared elements, and then it is a whole number written inside parentheses.There may be other numbers listed as well, depending on the periodic table. All periodic tables have a key as to what everything inside each block represents.
Why are atomic massed in the periodic table not whole numbers?
Most elements have something called 'Isotopes' which have the same Proton and Electron, but a different Neutron number. So as well as regular C-12, you can get C-14. The atomic mass in the periodic table takes this into account, and the figure it shows is an average, depending on how abundant each isotope is in a typical sample of that element.
