0
Why is the atomic mass of an element not a whole numbers while the atomic number is?
Wiki User
∙ 9y ago
Before I begin, you must understand that atomic number means the number of protons in the atom, and that the number of protons determines what element an atom is, i.e. an atom with 13 protons will always be aluminum, and one with 16 protons will always be sulfur. So, if you could somehow take away 3 protons from a sulfur atom, it would become aluminum. When the Atomic Mass of an element is shown with decimal places, this is an average of all the possible atomic masses that that element could have. Each element may have more than one atomic mass due to things called isotopes. These are not complicated - an isotope is just a version of an atom with a different number of neutrons in the nucleus than another version (isotope).
Remember that if the number of neutrons changes, the element will not change, as it is the number of protons that determines the element. Therefore, there can be multiple versions (isotopes) of the same element, with the same amount of protons, but with different numbers of neutrons. So, for example, the sodium atom, which will always have 11 protons in an atom (this is what makes it sodium), has 20 possible different isotopes (versions) ranging from 7 to 26 neutrons in each.
Therefore, you cannot work out a single atomic mass. It could be anywhere between 18 (11+7) and 37 (11+26) (here I am adding the constant proton (atomic) number of sodium to the highest and lowest possible neutron numbers to make two possible atomic masses). However, there will be many other possibilities for each neutron number in between 7 and 26. So, because of all these possibilities, the mean (average) is taken of all the possible atomic masses, which is often a decimal. This gives the best result which supports the many different isotopes available for a single element.
Wiki User
∙ 9y ago
Add your answer:
Earn +20 pts
Why is atomic number the proper basis for classification of elements?
Because Atomic number is the identity of an element , all the atoms of an element have the same atomic number while their mass numbers ma be different. for Example Argon(Ar) a noble gas and Calcium(Ca) an active metal have the same mass number 40.
What is the difference between the atomic number and atomic mass?
The atomic number is the number of protons in an atom of an element, while the atomic mass is the mass of protons and neutrons of a specific isotope of a given element.
Why is the atomic mass of an element not a whole number while the atomic number is?
The atomic number refers to the number of protons in the atom. Since the proton cannot be an in-between number, the atomic number will have to be a whole number. On the other hand, the atomic mass does not have to be a whole number because it is the mass of an atom and is roughly equivalent to the number of protons plus the average number of neutrons in that particular element.
What is larger the atomic mass or the atomic number?
The Atomic Number of an element is the number of Protons in its nucleus, that is what determines what element the atom is. The Atomic Mass is the total mass of Protons, Neutrons, and (negligable) Electrons, but that means the Atomic Mass will be larger than the Atomic Number.
What is the atomic mass of an element equal to atomic number or number of protons?
Answer:The atomic mass is NOT equal to both 'atomic number' and 'number of protons .The atomic mass of an element is by approximation equalto, but not exactly, the sum of protons and neutrons in the nucleus of the atom.The number of protons is given by the atomic number, not atomic mass.So, only the atomic number of an element AND the number of protons are equal. The atomic mass is also depending on the number of neutrons.More explicative:The atomic mass of an element refers to a particular isotope of that element, and is equal to the sum of the protons and neutrons in the nucleus of atoms of that isotope.For example, carbon-12 atoms have 6 protons and 6 neutrons, while carbon-14 atoms have 6 protons and 8 neutrons.Atomic weight, which is shown on the Periodic Table is a weighted average of the atomic masses of all the different isotopes of each element.For example, the atomic mass of C-12 is 12.0000 a.m.u. and the atomic mass of Carbon is 12.0107(8) g/molFrom the Periodic Table you can only tell the number of protons in the atoms of all of the isotopes of a given element, because the number of protons defines the element, and is the element's atomic number. However, you cannot tell the number of neutrons from the Periodic Table. You would have to look up the atomic masses of all the isotopes of each element in some sort of reference. The atomic number of an element is equal to the number of protons in the nucleus of an atom.
How many electrons and protons are in an element with an atomic?
put it in your mind! The Atomic number. is number of protons, While The Mass number. is number of protons and electrons. when you subtract both get the number of electrons and this for any element but not all elements have same atomic numbers or mass and Rutherford First discover "transmutation" from element to other element which determine by their atomic and mass numbers.
Why is atomic number the proper basis for classification of elements?
Because Atomic number is the identity of an element , all the atoms of an element have the same atomic number while their mass numbers ma be different. for Example Argon(Ar) a noble gas and Calcium(Ca) an active metal have the same mass number 40.
What is the maximum number of covalent bonds an element with atomic number 7 can make with an element with atomic number of 16?
It can make maximum 2 covalent bonds as element of atomic number 7 has 5 valence electrons while element having 16 atomic number have 6 valence electrons.
Why does Calcium have different mass numbers but same atomic number?
Atomic numbers are determined by the number of protons an atom has. The mass number is determined by the number of protons and neutrons. While the number of protons can't change (as the element itself would change), neutrons can and do vary. These are called isotopes.
Which element is heavier Copper or Tin?
Tin is heavier then Copper.Copper has an atomic number of 29, while Tin has an atomic number of 50.
What is the difference between the atomic number and atomic mass?
The atomic number is the number of protons in an atom of an element, while the atomic mass is the mass of protons and neutrons of a specific isotope of a given element.
What determines the atomic number of a substance?
The atomic number is the number of protons in the nucleus of an atom, while the atomic mass is the total mass of the nucleus (both protons and neutrons)
How are atomic mass and atom numbers related?
The mass number is the number of the Atomic Mass. The atomic mass is the mass of the atom of the element. There is no difference between the two, except mass number is referring to the number, while atomic mass is referring to the atom's mass in general, which is also expressed by a number. Basically, both terms mean the exact same thing.
Why is the atomic mass of an element not a whole number while the atomic number is?
The atomic number refers to the number of protons in the atom. Since the proton cannot be an in-between number, the atomic number will have to be a whole number. On the other hand, the atomic mass does not have to be a whole number because it is the mass of an atom and is roughly equivalent to the number of protons plus the average number of neutrons in that particular element.
What is the one thing that determines the identity of an atom that is whether it is an oxygen atom or a carbon atom?
The number of protons in the nucleus of an atom determines its identity as a particular element. The number of protons is the element's atomic number, and is unique to each element. For example, the atomic number of oxygen is 8, while the atomic number of carbon is 6.
What is larger the atomic mass or the atomic number?
The Atomic Number of an element is the number of Protons in its nucleus, that is what determines what element the atom is. The Atomic Mass is the total mass of Protons, Neutrons, and (negligable) Electrons, but that means the Atomic Mass will be larger than the Atomic Number.
Which has more protons sulfur or idoine?
Atomic number is equal to the number of protons of an element. Atomic number of sulphur is 16 while the atomic number of Iodine is 53. So iodine has more protons.
