From UPSC perspective, the following things are important :
Prelims level : Dmitri Mendeleev, Periodic table
Mains level : NA
Mendeleev was a Russian chemist and inventor who formulated the Periodic Law and the Periodic Table of Elements.
Chemistry can, no wonder, find their place in exam if core Biology could do in 2020 CSP.
Q.Which of the following statements is/are correct regarding the general difference between plant cells and animal cells?
- Plant cells have cellulose cell walls whilst animal cells do not.
- Plant cells do not have plasma membrane unlike animals cells which do
- Mature plant cell has one large vacuole whilst animal cell has many small vacuoles
Select the correct answer using the given code below-
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
- Mendeleev was born in the Siberian town of Tobolsk.
- In 1861, Mendeleev published a textbook named Organic Chemistry, which won him the Demidov Prize of the Petersburg Academy of Sciences.
- While explaining the chemical and physical properties of elements, he discovered similarities in the progression of atomic weights.
- He found that the order of atomic weights could be used to arrange the elements within each group and the groups themselves.
- Thus, Mendeleev formulated the periodic law. His Osnovy khimii (The Principles of Chemistry) became a classic, running through many editions and many translations.
The Periodic Law
- Using the Periodic Law, Mendeleev developed a systematic table of all the 63 elements then known.
- He even predicted the locations of unknown elements together with their properties within the periodic table.
- When these predicted elements, notably gallium ( 1875), scandium (1879), and germanium (1886) were discovered, Mendeleev Periodic Table began to gain wide acceptance.
- Incidentally, in 1870, German chemist Julius Lothar Meyer also published a paper describing the same organisation of elements as Mendeleev’s. But the latter is given credit for the table.
- In all, Mendeleev predicted 10 new elements, of which all but two turned out to exist. Element 101 is named Mendelevium in his honour.