Atomic number is a unique number for each element. No two elements have the same atomic number. Atomic number is also the number of protons in the nuclei of the atoms of any given atom. Atomic Mass, however, is the number of protons, neutrons and electrons. The number of neutrons can vary with different isotopes of the same element, this means that atomic mass can vary with different isotopes. So atomic number does not vary, but atomic mass does, so it is more logical to use atomic number to organize the elements. In addition, when the elements are arranged according to atomic number into seven rows and 18 columns, it becomes evident that there are certain trends that occur across the periods, and that elements in the same group have similar properties.
In 1869 Russian teacher and scientist Dmitri Mendeleev, presented a periodic table of the elements based on atomic weights. The current periodic table is arranged by the atomic numbers of the elements.
1.) The atomic mass in Mendeleev's periodic table does not increase regularly. therefore, it was impossible to predict the number of elements between two elements.The Modern periodic table has been made according to the increasing atomic number (Modern Periodic Law states that 'The properties of an element are the periodic function of its atomic number). The atomic number gives us the number of protons in the nucleus of an atom. the atomic number increases by one as we go from one element to the next. thus, this makes it easy to ascertain how many undiscovered elements may be there between two known elements.2.) Mendeleev's periodic table was made according to increasing atomic masses. we know that of an element have same chemical properties and atomic number, but different atomic masses. So, the concept of isotopes can not be satisfied.The Modern periodic table is according to increasing atomic numbers. Therefore, the problem of isotopes is easily dealt with.
The elements are simply Tellurium and Iodine that didn't obey Mendeleev's law because the elements' atomic mass are not following along on the fifth row or period of the normal periodic table today's use.
No two elements may have the same atomic number. But two elements may have same atomic mass. Hence atomic number is better than atomic mass.
Mendeleev's periodic table was based on the atomic masses of elements. However, this was not effective when isotopes were discovered. An isotope of an element is defined as the element having the same atomic number but varying mass numbers. So, mass numbers weren't constant and hence, a better characteristic was chosen -atomic number. Atomic number of any element was a characteristic of a particular element. Hence atomic numbers were taken as the basis of classification instead of atomic masses.
Improvements in technology, such as the invention of spectroscopy and X-ray crystallography, allowed scientists to better understand the properties of elements and their atomic structures. This knowledge was crucial for organizing the elements into the periodic table based on their atomic number and properties, leading to the periodic table we use today.
Chemists organized the elements by properties, specifically by atomic mass, to create the periodic table. This organization allowed them to identify patterns and trends among elements based on their chemical behavior. The periodic table was further refined over time as new elements were discovered and their properties were better understood.
The atomic number that sodium has in periodic table is 11 and valency is 1. The periodic table is a kind of table that was invented for the better study of elements and other types of compound. It makes the systematic study of elements.
In 1869 Russian teacher and scientist Dmitri Mendeleev, presented a periodic table of the elements based on atomic weights. The current periodic table is arranged by the atomic numbers of the elements.
Well, Back when Medeleev made this table, many of the elements were not even discovered yet. He plotted only the elements that he knew on his table. He organized them by increasing atomic weight. He didn't know all the elements so he would put question marks and empty spaces in the spots he thought elements would be and left to be found by other scientist. He happened to be true about the missing elements and that scientist did end up finding these "missing links" of the periodic table and led to the new or modern periodic table. The modern periodic table doesnt have any missing elements and they changed Medeleev's way of organizing the table by increasing atomic weight to increasing atomic number. So the newer form of the periodic table was complete and made it easier to find what elements react better with other elements. This making the modern table became the more efficent table of our time.
The periodic table created by Mendeleev in 1869 was based on atomic mass and grouped elements with similar properties together. Moseley improved upon this by arranging elements based on atomic number, leading to the modern periodic table where elements are arranged in order of increasing atomic number, which is the number of protons in the nucleus. This organization better reflects the physical and chemical properties of elements.
1.) The atomic mass in Mendeleev's periodic table does not increase regularly. therefore, it was impossible to predict the number of elements between two elements.The Modern periodic table has been made according to the increasing atomic number (Modern Periodic Law states that 'The properties of an element are the periodic function of its atomic number). The atomic number gives us the number of protons in the nucleus of an atom. the atomic number increases by one as we go from one element to the next. thus, this makes it easy to ascertain how many undiscovered elements may be there between two known elements.2.) Mendeleev's periodic table was made according to increasing atomic masses. we know that of an element have same chemical properties and atomic number, but different atomic masses. So, the concept of isotopes can not be satisfied.The Modern periodic table is according to increasing atomic numbers. Therefore, the problem of isotopes is easily dealt with.
Moseley established a more accurate periodic table by arranging elements in order of increasing atomic number rather than atomic mass. This led to the modern periodic table where elements are organized by their atomic number, which reflects the number of protons in their nuclei. This arrangement helped to better predict the properties of elements and fill in gaps in the table.
The elements are simply Tellurium and Iodine that didn't obey Mendeleev's law because the elements' atomic mass are not following along on the fifth row or period of the normal periodic table today's use.
Chemists in the early 1900s made changes to Mendeleev's periodic table by rearranging elements based on their atomic number instead of atomic mass, leading to the development of the modern periodic table. This change accurately emphasized the relationship between an element's properties and its atomic number, rather than its atomic mass, and helped to better organize the elements.
Henry Moseley contributed to the periodic table by arranging elements based on atomic number rather than atomic mass, establishing the modern periodic law. His work led to a more accurate arrangement of elements and a better understanding of their properties. Moseley's discovery helped fill gaps in the periodic table and laid the foundation for the modern understanding of the structure of atoms.
At first, he organized it by increasing atomic mass. This caused some continuity and periodicity problems, however, and was later reorganized by increasing atomic number. This worked better, and is the way we have it organized today.