0
Why are the masses of the elements on the periodic table a decimal number?
Wiki User
∙ 13y ago
The decimal is the average Atomic Mass of an element.
Each element has a set of isotopes which have different numbers of neutrons and therefore different atomic masses.
For example there are 3 isotopes of carbon. with masses of 12, 13 and 14, though carbon-12 is the most common by far. But because of the two heavier isotopes the average mass is 12.011 rather than just 12.
Wiki User
∙ 13y ago
Wiki User
∙ 12y agoNot all elements exist in a single form. Some elements such as chlorine exist as isotopes (atoms of the same element with different number of neutron but the same number of electrons and protons) as neutron are contribute to a large fraction of the atom's weight one more or one less will cause a large difference in relative atomic weight.
Chlorine has chlorine-35 and chlorine-37. 35 is roughly 70%of all chlorine so they take the percentages and multiply each weight and add them together to get an average weight based on the percentage of chlorine they comprise of in real life.
Long story short (70%)(35/100) + (30%)(37/100) makes out to 35.5(atomic weight of chlorine) the decimal is a result of taking *average*.
Remember 70% and 30% are not the exact figures I don't want to look them up but this roughly explains the concept.
Wiki User
∙ 13y agoBecause that # is the exact mass of the element but u usually round up or down =)
Add your answer:
Earn +20 pts
What is the basis of arranging the elements in the periodic table?
increasing atomic number and repeating properties
What are some ways that elements are arranged on the periodic table of elements?
Mendeleev arranged the elements in a table in the increasing order of atomic masses and repeating periodic properties. In the modern long-form of periodic table, the elements are arranged in the increasing order of atomic number and repeating periodic properties.
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.
Why does the atomic mass on the periodic table progressively changes left to right and top to bottom why?
Because there are increasingly more protons, electrons, and neutrons. Atomic mass is the average number of neutrons in all of the isotopes(different types) of a specific element, meaning you can sometimes have decimal masses. But, the atomic number is never a decimal because the atomic number is just a numbering system for all the elements.
How are elements organize?
by their atomic number in the periodic table by grouping the elements on the periodic table
What is the basis of arranging the elements in the periodic table?
increasing atomic number and repeating properties
What are some ways that elements are arranged on the periodic table of elements?
Mendeleev arranged the elements in a table in the increasing order of atomic masses and repeating periodic properties. In the modern long-form of periodic table, the elements are arranged in the increasing order of atomic number and repeating periodic properties.
How were the atomic number and the atomic masses of the elements determined?
Atomic masses are determined by mass spectrometry. The atomic number is identic with the number of protons in the atom - depends on position in the periodic table.
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 does a periodic table have?
a modern periodic table should have the 118 elements, their atomic numbers, and their masses. to find the number of protons and electrons, they are the same as the atomic number. to find the neutrons, subtract the protons from the mass.
How are elements are arranged on periodic table?
Dmitri Mendeleev and Lothar Meyer first arranged the elements in the increasing order of atomic masses. Bohr and Henry Moseley then arranged the elements in the increasing order of atomic number.
How are the elements arranged?
atomic number
How can you compare and contrast the periodic table that Mendeleev developed to the periodic table that Mosley organized?
Mendeleev used atomic masses to classify the element, where as Moseley classified the element in terms of atomic number, he suggested that chemical and physical properties are the functions of the atomic number Elements in the periodic table is classified as Metals, Nonmetal and Metalloids. Normally Group 1 to 12 are metals... Sayed Abdul Aziem Sayed_abd2007@hotmail.com
Why did they number elements on periodic table?
No one give number to elements in periodic table. they have been calculated
Why does the atomic mass on the periodic table progressively changes left to right and top to bottom why?
Because there are increasingly more protons, electrons, and neutrons. Atomic mass is the average number of neutrons in all of the isotopes(different types) of a specific element, meaning you can sometimes have decimal masses. But, the atomic number is never a decimal because the atomic number is just a numbering system for all the elements.
How do you find protons in elements on the periodic table?
It's the same as the Atomic number, which is the number on an element that usually has no decimal, and is the first number listed. Same goes for electrons.
Who arranged the periodic table in masses?
Russian chemist Dimitri Mendeleev started the development of the periodic table, arranging chemical elements by atomic mass. He predicted the discovery of other elements, and left spaces open in his periodic table for them.
