Chemistry
'The periodic table contains elements methodically grouped together'. State the main helpful features of the long form of the periodic table.
Answer
The main helpful features of the long form of the periodic table are —
- Till date about 118 elements have been discovered and the study of the properties of each element is a difficult and tedious process. The periodic table containing elements methodically grouped makes the study simpler and systematic.
- The periodic table makes arrangement of elements easy and simple to reproduce as it separates the elements with respect to their nature.
- Elements in a group have similar or graded properties. Thus, if the properties of one member of a group is known the properties of the other members of the group could be correlated.
- Periodic properties that reappear at regular intervals are seen across periods.
Related Questions
Write short notes on the following types of elements –
transition and inner transition elements
Write short notes on the following types of elements –
normal elements
Name or state the following with reference to the elements of the first three periods of the periodic table.
(a) The noble gas having duplet arrangement of electrons.
(b) The noble gas having an electronic configuration 2, 8, 8.
(c) A metalloid in period 2 and in period 3.
(d) The number of electron shells in elements of period 1, period 2 and period 3.
(e) The valency of elements in group 1 [IA].
(f) The group whose elements have zero valency.
(g) An alkaline earth metal in period 3.
(h) The non-metallic element present in period 3 other than sulphur and chlorine.
(i) A non-metal in period 2 having electronic configuration 2, 6.
(j) An electrovalent compound formed between an alkali metal and a halogen.
(k) A covalent compound formed between an element in period 1 and a halogen.
(l) An alkali metal in period 3 which dissolves in water giving a strong alkali.
(m) A metal in period 3 having valency 3.
(n) The bridge elements of period 3 of group 1 [IA], 2 [IIA] and 13 [IIIA].
(o) The periods which contain the inner transition elements.
(p) The formula of the hydroxide of the element having electronic configuration 2, 8, 2.
(q) The valency of the element in period 3 having atomic number 17.
(r) A non-metal in period 2 which is tetravalent.
Select the correct answer from the words in bracket.
- He arranged elements in increasing order of atomic numbers. [Dobereiner/ Moseley / Mendeleeff
- Is a metal in period 2 having electronic configuration 2, 1. [Beryllium / Lithium / Sodium]
- Is a period having elements from atomic no. 11 to 18. [period – 1/2/3]
- The most reactive halogen from group 17. [chlorine/fluorine/bromine]
- Is the group number of the element whose atomic number is 4. [group - 1/group – 2/group – 18]