In the year 1870, only ……… elements were known.
a) 76
b) 118
c) 105
d) 105
….……. attempted to classify the elements systematically.
a) Lavoisier
b) Mendeleev
c) Newlands
d) All of these
In ……….. Lavoisier classified the elements.
a) 1787
b) 1864
c) 1869
d) 1974
Explanation:Lavoisier classified elements into metals and nonmetals. This classification was based on certain distinctive physical properties such as hardness, malleability and luster. On the basis of these properties, sodium and lead were classed together as belonging to the group of metals.
In 1864 ………. classified the elements.
a) Newlands
b)Einstein
c) Mendeleev
d)Newlands
Explanation:John Newlands put forward his law of
octaves in 1864 in which he arranged all the elements known at the time
into a table in order of relative atomic mass. When he did this, he found that
each element was similar to the element eight places further on. ... As a
result, his table was not accepted by other scientists.
In ………. Mendeleev arranged
the elements successfully.
a) 1869
b) 1974
c) 1864
d)
1870
Explanation:Dmitri Ivanovich Mendeleev was a Russian
chemist and inventor. He is best known for formulating the Periodic Law and
creating a farsighted version of the periodic table of elements.
Mendeleev arranged the elements on the basis of ………
a) atomicity
b) atomic number
c) atomic mass
d) all of these
Explanation:Russian chemist who developed the periodic classification of the elements. Mendeleev found that, when all the known chemical elements were arranged in order of increasing atomic weight, the resulting table displayed a recurring pattern, or periodicity, of properties within groups of elements.
