Classification of elements and Periodicity in Properties

Question 1

Mendeleev’s Periodic law

Answer 1

the physical and chemical properties of elements are the periodic function of their atomic masses

Question 2

contributions of Mendeleev’s periodic table

Answer 2

💎systematic study of chemistry
💎the discovery of new elements
💎correction of atomic masses

Question 3

defects of Mendeleev’s periodic table

Answer 3

💎position of isotopes
💎position of hydrogen
💎variable valency
💎position of lanthanide and actinoids

Question 4

modern periodic law

Answer 4

the physical and chemical properties of elements are the periodic function of their atomic numbers

Question 5

merits of modern periodic law

Answer 5

the periodic table is closely connected to the electronic conf. of elements.
the elements posses similar type of electronic conf. and similar physical and chemical properties

Question 6

demerits of modern periodic table

Answer 6

the position of hydrogen is still not well-defined
helium is an exception
lanthanoids and actinoids have not been accommodated in the main body

Question 7

periodicity

Answer 7

the periodic reptition of elements having similar properties after regular interval

Question 8

reason of periodicty

Answer 8

recurrence of similar electronic configuration occurs at regular intervals in periodic table,

Question 9

covalent radius

Answer 9

one half of the distance between the centers of the nuclei of two similar atoms bonded together by the single covalent bond.

Question 10

Vander Walls’ Radius

Answer 10

one half of the distance b/w two atoms of same substance joined together at their closet approach

Question 11

Crystal radius

Answer 11

one half of the distance between the centre two adjacent atoms joined in a metallic crystal.

Question 12

atomic volume

Answer 12

volume occupied by the one gram atom of that element

Question 13

isoelectronic ions

Answer 13

the ions of different elements that possess same arrangement of electrons but differ in nucleur charge

Question 14

isoelectronic ions

Answer 14

the ions of different elements that possess same arrangement of electrons but differ in nucleur charge

Question 15

ionization energy

Answer 15

the amount of energy required to remove an electron from the isolated neutral gaseous atom

Question 16

electron gain enthalpy

Answer 16

the amount of energy released to add an electron ion the outermost shell of isolated neutral gaseous atom

Question 17

ionic radii

Answer 17

ionic radius of the ion may be defined as the distance from its nucleus to the point upto which the nucleus has influence on the electronic cloud of the ion

Question 18

electronegativity

Answer 18

the tendency of the electronegative atom to attract the shared pairs of electrons