Periodic classification of elements

In mendeleev's periodic table, gap was not left for one of the following elements

• Gallium

• Beryllium

• Germanium

• Scandium

The three elements having chemical symbols of Si, B and Ge are-

• All metals

• All non metals

• All metalloids

• Si is metalloid

  B is metal

  Ge is non metal

The three imaginary elements X, Y and Z represent a dobereiner triad. If the atomic mass of element X is 14 and that of element Y is 46 then atomic mass of elements Z will be

• 28

• 30

• 78

• 60

An element X forms an oxide of X²O³. In which of the following group of mendeleev's periodic table is this element placed

• Group 2

• Group 3

• Group 5

• Group 8

Which one of the following does not increase while moving down the group of the periodic table ?

• Atomic radius

• Metallic character

• Valence electron

• Shells in the atom

The first periodic table was given by

• Mendeleev

• Newland

• Dobernier

• Moseley

___________ elements were known when mendeleev presented the periodic table

• 63

• 65

• 64

• 92

Which was the first classification of elements ?

• Newlands law of octaves

• Dobernier Triads

• Metal and non metal

• Mendeleev periodic table

Which of the following were not included in the mendeleev periodic table ?

• Halogens

• Alkali metal

• Non metals

• Isotopes

Eka boron is

• Germanium

• Gallium

• Scandium

• Aluminum