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An element's Atomic Mass is actually a weighted average of all the masses of all the isotopes of that element. Every element has a certain number of isotopes, which are different versions of that element. Different, because they have varying numbers of neutrons. Neutrons have mass, so non-standard numbers of neutrons makes isotope atoms weigh differently than the normal version of that atom. For example, carbon typically has 6 protons and 6 neutrons. So you would think that carbon's atomic mass would be 12. However, there is a small amount of carbon out there that has either 7 or 8 neutrons, which makes these atoms weigh more. This is why carbon's atomic mass on the perioidic table is slightly more than 12. In the case of most elements, isotopes make up a relatively small percentage of the total, which is why many atomic masses are very close to a whole number, but not quite.

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What is the difference between atomic mass number and atomic number?

Atomic mass number is the average atomic mass for that element, which is : All the isotopes' masses known for that element averaged up. Atomic number is the element's "identity", the number of protons the element and all its isotopes have. All the isotopes of a given element will have different number of electrons and neutrons, but the protons of the element never will change.


What number never changes in a neutral atom?

The number of protons in the nucleus never changes in a neutral atom. This is because the number of protons determines the element's identity.


Definition of atomic mass and atomic number?

the atomic number: The number of protons in the nucleus of an atom determines an element's atomic number. In other words, each element has a unique number that identifies how many protons are in one atom of that element. For example, all hydrogen atoms, and only hydrogen atoms, contain one proton and have an atomic number of 1. All carbon atoms, and only carbon atoms, contain six protons and have an atomic number of 6. Oxygen atoms contain 8 protons and have an atomic number of 8. The atomic number of an element never changes, meaning that the number of protons in the nucleus of every atom in an element is always the same. the atomic mass: it's the sum of neutrons and protons electrons in a single atom. to sum it up the atomic number is the number of protons and the mass number is the total number of every thing in an atom!


Is The atomic number is always equal to the atomic weight?

No.The atomic number is dependent on the number of protons. The atomic weight is dependent on the number of protons and neutrons. As almost every element has some neutrons in its nucleus the atomic number will never be equal to the atomic weight.The one possible exception is Hydrogen with a single proton. However there are two isotopes of hydrogen: deuterium and tritium. Deuterium has one proton and one neutron. Tritium has one proton and two neutrons. Therefore when taken as a whole the atomic weight of hydrogen will always be slightly greater than 1g/mole.


What does it mean to say the atomic number in an atom?

The atomic number of an atom is the number of protons in its nucleus. It determines the element's identity on the periodic table and is used to arrange elements in ascending order based on their properties.

Related Questions

Which number for an isotope is the neutron number?

The number of neutrons is never directly displayed.For a given isotope of an element, the "top number" (e.g. 14C or carbon-14) is the atomic mass number, the total of neutrons and protons. To find the number of neutrons, subtract the atomic number from the isotopes atomic mass number. Here, 14C will have 8 neutrons.


What is the difference between atomic mass number and atomic number?

Atomic mass number is the average atomic mass for that element, which is : All the isotopes' masses known for that element averaged up. Atomic number is the element's "identity", the number of protons the element and all its isotopes have. All the isotopes of a given element will have different number of electrons and neutrons, but the protons of the element never will change.


Why is the atomic number on the periodic tabe never a whole number?

The question is based on a complete lack of understanding as to what the atomic number is! They are always, without exception, whole numbers.


What element can have the atomic number 118 and also the mass number 50?

No element can have those features; the mass can never be less than the atomic number in any element.


What quantity of an element in the periodic table never changes?

The atomic number


Why is the relative atomic mass of chloride not a whole number?

Because relitive atomic masses are NEVER whole numbers.


What number never changes in a neutral atom?

The number of protons in the nucleus never changes in a neutral atom. This is because the number of protons determines the element's identity.


Can the mass number of the atom ever be smaller than its atomic number?

No. The atomic number only counts the number of protons or electrons in an atom, but the mass number counts at least the number of protons, sometimes the electrons and the number of neutrons if any. The closest they will get is being the same (Hydrogen with AN=1, MN=1), but the mass number will almost always be bigger than the atomic number.


Definition of atomic mass and atomic number?

the atomic number: The number of protons in the nucleus of an atom determines an element's atomic number. In other words, each element has a unique number that identifies how many protons are in one atom of that element. For example, all hydrogen atoms, and only hydrogen atoms, contain one proton and have an atomic number of 1. All carbon atoms, and only carbon atoms, contain six protons and have an atomic number of 6. Oxygen atoms contain 8 protons and have an atomic number of 8. The atomic number of an element never changes, meaning that the number of protons in the nucleus of every atom in an element is always the same. the atomic mass: it's the sum of neutrons and protons electrons in a single atom. to sum it up the atomic number is the number of protons and the mass number is the total number of every thing in an atom!


Are there atomic bombs now?

Yes there are a number of countries that have atomic wepons. However since WW2 an atomic bomb has never been set off in anger.


Is The atomic number is always equal to the atomic weight?

No.The atomic number is dependent on the number of protons. The atomic weight is dependent on the number of protons and neutrons. As almost every element has some neutrons in its nucleus the atomic number will never be equal to the atomic weight.The one possible exception is Hydrogen with a single proton. However there are two isotopes of hydrogen: deuterium and tritium. Deuterium has one proton and one neutron. Tritium has one proton and two neutrons. Therefore when taken as a whole the atomic weight of hydrogen will always be slightly greater than 1g/mole.


What does it mean to say the atomic number in an atom?

The atomic number of an atom is the number of protons in its nucleus. It determines the element's identity on the periodic table and is used to arrange elements in ascending order based on their properties.