(a) Main group elements (b) Noble gases (c) Transition elements (d) Inner transition elements
Answers
Answer:
(a)helium,lithium,boron,carbon,nitrogen
(b) Noble gases are inert gases.krypton, argon,xenon etc.
(c)these are the elements which are partly filled in their electronic configuration.Sc,Te,Cr,Mn
(d) These are the elements which lies between 2nd and 3rd series in D block elements.lanthnoids and actnoids
Answer:
Explanation:
(i) Elements placed in two separate rows at the
bottom of the periodic table are called inner
transition elements.
(ii) They include two series of elements: Lanthanide
series and Actinide series. They belong to f-block
elements of Modern Periodic table.
(iii) 14 elements with atomic number 58 to 71
(Cerium to Lutetium) are called lanthanides.
These elements are placed along with lanthanum
(La = 57) in group 3 and period 6 because of very
close resemblance in properties between them.
(iv) 14 elements with atomic number 90 to 103
(Thorium to Lawrencium) are called actinides.
These elements are placed along with actinium
(Ac = 89) in group 3 and period 7 because of very
close resemblance in their properties.
(v) They have last three shells incompletely filled.