2nd & 3rd periods are also called ……. period
a) long
b) very long
c) shortest
d) short
4th and 5th periods have……..elements each.
a) 56
b) 2
c) 8
d) 18
4th and 5th periods contain eight elements called ………
a) noble gases
b) representative elements
c) transition element
d) none of these
Explanation:The Groups of periodic table can divided into the two categories.Representative Elements &Transition Metals. First two and last six groups of periodic table together are representative elements. Transition metals falls in the middle of
periodic table.
6th period containing elements……….
a) 18
b) 16
c) 32
d) 36
In 6th period ……elements are Lanthanides.
a) 10
b) 12
c) 14
d) 17
Explanation:The lanthanide or Lanthanides series of chemical elements comprises the 15 metallic chemical elements with atomic numbers 57–71, from lanthanum through lutetium. These elements, along with the chemically similar elements scandium and yttrium, are often collectively known as the rare-earth elements or rare-earth metals.
Lanthanides series is present in ……. period.
a) 5th
b) 6th
c) 3rd
d) 7th
