(2) Explain s, p, d and f block elements with the help of following questions.
(i) Which group forms the p block?
(ii) Which block elements are also called as transition elements?
(iii) Where do the metalloid elements lie?
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Answers
Answer:
S
s-Block Elements -
Elements in which the last electron enters the s-orbital of the outermost energy level are called s-block elements.
The s-block consists of two groups—Group 1 and Group 2, which are alkali metals and alkaline earth metals.
P
p-Block Elements -
Elements in which the last electron enters the p-orbital of their outermost energy level are called p-block elements.
The p-block elements comprise elements belonging to Groups 13−18.
It consists of all types of elements—metals, non-metals and metalloids.
D
d-Block Elements (Transition Elements)
Elements in which the last electron enters any one of the five d-orbitals of penultimate shells are called d-block elements.
Elements of Groups 3−12 in the center of the periodic table constitute the d-block elements.
The general outer electronic configuration of d-block elements is (n − 1)d1−10 ns1−2.
F
f-Block Elements (Inner Transition Elements)
Elements in which the last electron enters any one of the seven f-orbitals of their respective ante-penultimate shells are called f-block elements.
There are 28 f-block elements in the periodic table which are placed at the bottom of the periodic table.
The lanthanides or lanthanoids, i.e. cerium to lutetium (58Ce – 71Lu) and actinides or actinoids, i.e. thorium to lawrencium (90Th – 103Lr) are characterised by the outer electronic configuration (n – 2) f0−14 (n – 1)d0-2ns2.
All the f-block elements, i.e. lanthanides and actinides, are also called inner transition elements.