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Why is the accurate molecular mass of many element not a whole number?
Wiki User
∙ 13y ago
The Atomic Mass shown on the periodic chart is the weighted average of the naturally occurring isotopes of that element.
It works like this: What is the average weight of 4 people where three weigh 120 and one weighs 90? (In this group, the most common weight is 120 so the average will be close to 120) The weighted average is:
75% x 120 + 25% x 90 = 90 + 22.5 = 112.5
All of the member's weights were whole numbers but the average is a fraction.
Each isotope, similarly, has a whole number weight but they occur at different percentages.
If you see a whole number weight on the periodic chart it is the weight of the longest-lived isotope since it has no naturally occurring stable isotopes...you will sometimes see this weight in parentheses.
Wiki User
∙ 13y ago
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The mass number of an element is equal to what of an element?
The sum of the number of protons and the number of nuetrons.
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.
What would cause the average atomic mass to be close to a whole number?
The average atomic mass of an element would be closer to a whole number if there were few to no electrons. This means having little to no electrons in the element's isotopes.
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 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.
Is 1 the identity element or a whole number?
1 is a whole number. It is the identity element with respect to multiplication but not addition.
Does the mass number of an element have to be a whole number?
Approximately, yes. But the mass number is an average of the masses of the isotopes of the element, weighted together according to their abundance. This averaging of different whole numbers results in the mass number not being a whole number.
What element has the atomic number for 3.14?
No element has this atomic number. All atomic numbers are whole numbers.
Why an accurate value of Ar is not a whole number?
because it is a decimal
Is zero the identity element for whole number-multiplicaton?
No.
What do whole numbers on the periodic table represent?
The whole number, the one at the top, above the element's symbol in the element box, is the atomic number. The atomic number is the number of protons per atom in that particular element. The bottom number, that is always a decimal, is the atomic mass.
The mass number of an element is equal to what of an element?
The sum of the number of protons and the number of nuetrons.
Why is the atomic mass of an element usually not given as a whole number even though each individual atom of the element has a whole number of protons and neutrons?
It's the electrons that throw it off.
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 you round 25.99934 to be accurate?
That depends on what you mean by accurate. The number as it is, is accurate. If you are looking for a whole number, it will round up to 26 because of the digit being 9 in position after the decimal point.
Which number in an element box on the periodic table is the atomic number?
The atomic number is the whole number indicating the number of protons. It is usually directly above or below the element symbol.
Can a molecular formula have subscripts that are multiples of a whole number ratio?
Yes, however most molecular formulas are reduced to Lowest Common Multiples for ease of understanding.
