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Two sample of carbon have the same atomic number but different atomic masses Why do the two samples have different atomic number?
ISOTOPE
The answer is that, first, different atoms of the same element will not have different atomic numbers because the identity of an element is determined by the number of protons in its nucleus. And the number of protons of an atom is its atomic number. Pick any atom of that element and it will have that unique number of protons. Elemental identity and proton count are inseparably linked. Said another way, all of the atoms of that element will have the same atomic number - the same number of protons. Electrons can come and go, being borrowed or loaned out in chemical activity, but the proton count remains constant for a given element. Now to the Atomic Mass.
It turns out that for a given atom (and that atom will have a fixed number of protons), the number of neutrons can vary. Said another way, the number of neutrons in any atom of a given element can be different from one atom of that element to another atom of that element. We say that a given element has different isotopes. It has its fixed number of protons, but the number of neutrons isn't fixed. Each isotope has that same characteristic number of protons, but the number of neutrons can vary from one atom to the next. Let's take an example.
Lithium has 3 protons in its nucleus. Every atom of lithium is like this. Its atomic number is three. Always. But what about neutrons? It turns out that there are two stable configurations possible. One has 3 neutrons. Its atomic mass is about 6.015 or so. Recall that subtracting the atomic number from the atomic mass gives us the number of neutrons in the nucleus of that atom. The 6.015 minus the 3 yields an answer of 3 for the number of neutrons. There is also a lithium atom that has 4 neutrons in its nucleus. Its atomic mass is about 7.016 or so. Same math. Take the 7.016 and subtract the 3 and get 4 as the answer - and the number of neutrons in the nucleus of that atom. Those are the two stable isotopes of lithium. (There are a number of other isotopes of lithium, but they're all unstable and disappear fairly quickly after being made in the physics lab.)
Pick any other element and it will have a unique identity based on the number of protons in the nucleus. But it will have different numbers of neutrons as you look around at different atoms of that element. The different numbers of neutrons account for the different atomic masses of given isotopes of that element.
What else can I help you with?
What atoms with same atomic number but different atomic masses?
Isotopes are atoms with the same number of protons (same atomic number) but different numbers of neutrons, leading to different atomic masses. For example, carbon-12 and carbon-14 are isotopes of carbon with atomic number 6 but atomic masses of 12 and 14 respectively.
State the name and the mass of the isotope relative to which all atomic masses are measured?
The isotope used as the reference for atomic masses is carbon-12, with a mass of 12 atomic mass units (amu).
The atomic weight scale is based upon international agreement that?
the atomic weight scale is based upon the relative atomic masses of elements compared to carbon-12, which has an assigned value of 12. This standardization allows for consistency and accuracy in comparing the masses of different elements.
Carbon exists as 12c6 and 14c6 these different forms of the same element are known as?
Isotopes. These are atoms of the same element with different numbers of neutrons, resulting in different atomic masses.
Why is the relative atomic mass of an element relative to carbon-12?
The relative atomic mass of an element is compared to carbon-12 because carbon-12 is used as a standard reference point for measuring atomic masses. This comparison helps scientists determine the mass of atoms of different elements in relation to each other.
What atoms with same atomic number but different atomic masses?
Isotopes are atoms with the same number of protons (same atomic number) but different numbers of neutrons, leading to different atomic masses. For example, carbon-12 and carbon-14 are isotopes of carbon with atomic number 6 but atomic masses of 12 and 14 respectively.
Which refers to atoms with the same atomic number but different atomic masses?
They are called isotopes. eg we have different isotopes of carbon
The current standard for atomic masses is?
The current standard for atomic masses is based on the Carbon-12 isotope. It is defined as exactly 12 atomic mass units (amu), with all other atomic masses determined relative to it. This standard allows for consistency in measurements and comparisons of atomic masses across different elements.
What atom is standard for atomic masses?
Carbon (12).
Are all sample of elements are composed of atoms with same atomic mass?
No, different samples of an element can have varying atomic masses due to the presence of isotopes. Isotopes are atoms of the same element with different numbers of neutrons, leading to different atomic masses.
What nuclide is used as the standard in the relative scale for atomic masses and What is it's assigned atomic mass?
Carbon-12 (12C) is used as the standard in the relative scale for atomic masses, and its assigned atomic mass is 12 atomic mass units.
What nuclide is used as standard relative scale for atomic masses?
Carbon-12 is used as the standard relative scale for atomic masses. This is defined as having a mass of exactly 12 atomic mass units (u). Other elements are compared to this standard to determine their atomic masses.
What element are atomic masses of all element based on?
carbon
State the name and the mass of the isotope relative to which all atomic masses are measured?
The isotope used as the reference for atomic masses is carbon-12, with a mass of 12 atomic mass units (amu).
The atomic weight scale is based upon international agreement that?
the atomic weight scale is based upon the relative atomic masses of elements compared to carbon-12, which has an assigned value of 12. This standardization allows for consistency and accuracy in comparing the masses of different elements.
Do carbon 12 and 14 have the same atomic mass?
No. They have different masses, but the same atomic number. Carbon-12 has a mass number of 12 and atomic number of 6, and carbon-14 has a mass number of 14 and atomic number of 6. The difference in mass number is due to different numbers of neutrons. Carbon-12 atoms have 6 neutrons and carbon-14 atoms have 8 neutrons.
What is Atomic Mass unit based on?
The atomic mass unit (u) is based on the mass of a carbon-12 atom, which is defined as exactly 12 atomic mass units. This standard allows scientists to compare the masses of different atoms based on their atomic masses relative to carbon-12.
