What patterns were observed by Mendeleev
Answers
1. He arranged all the 63 known elements in the increasing order of their atomic masses.
2. The table consists of vertical columns called groups and horizontal rows called periods.
3. The elements with similar physical and chemical properties were placed under the same group in the form of sub-groups
Dmitri Mendeleev, a Russian chemist and teacher, devised the periodic table — a comprehensive system for classifying the chemical elements.In the mid-1700s, chemists began actively identifying elements, which are substances made up of just one kind of atom. But a century later, they still used a variety of symbols and acronyms to represent the different materials — there just wasn’t a common lexicon. In 1869, the Russian chemist Dmitri Mendeleev came to prominence with his tabular diagram of known elements. This basic ingredient list, of which all matter exists, became known as the periodic table. Here’s what’s especially amazing: Mendeleev’s chart allotted spaces for elements that were yet to be discovered. For some of these missing pieces, he predicted what their atomic masses and other chemical properties would be. When scientists later discovered the elements Mendeleev expected, the world got a glimpse of the brilliance behind the periodic table.