Q.No 1. Discuss various types of radii.
Ans. Because of the vague concept of atomic radius, a number of radii have been defined for an atom which pertain to different types of bonding between the atoms. Some of these radii are:
Covalent radii.
Covalent radius of atom is equal to one- half of the inter-nuclear distance.
Crystal Radius. (Atomic and metallic radius) .
The crystal radius as defined as one-half of the distance between the nuclei of two adjacent metal atoms in the closely packed metallic crystal.
Van DER Waals radius.
When two non-bonded isolated atoms of two adjacent molecule of an element in the solid state approach each other without overlapping their electron clouds to form a bond between them, they cannot come closer than a minimum distance without forming a bond.This minimum distance is called van DER Waals distance and half of the this distance is called van DER Waals radius.
Q No.2 Discuss the variation of atomic and ionic radii in a period and a group.
Ans. In a period. The number of shells in the period remain same in all the elements of period,but the value of effective nuclear charge increases from left to right. This increase nuclear charge pulls the electron cloud of the atom nearer to the nucleus and this the size of atom and ions goes on decreasing from left to right.Thus in going from left to right in a period, atomic and ionic Raffi decreased with the increase of atomic number.
In a group. In going down a group, the atomic and ionic radii both increase with the increase of atomic number. The number of shells increases from top to bottom in a group, this due to increase of shell, number of atomic and ionic radii increase in a group.
Q.No.3 why a cation is smaller in size than it's parent atom.
Ans. Cation is formed by the removal of one or more electrons from the atom. Thus a cation has smaller number of electrons than it's parent atom.with the decrease of number of electrons,the magnitude of effective nuclear charge increases, which pulls the electrons cloud of the cation nearer to the nucleus and thus makes the cation smaller in size than it's parents neutral atom.
Q.No.4 why an anion is bigger in size than it's parent atom.
Ans. An anion is formed by adding one or more electrons to the neutral atom.Thus anion has more electrons than it's parent atom. With the increase of number of electrons, the magnitude of effective nuclear charge decreases, which pulls the electron cloud of anion outward away from the nucleus and thus makes the anion large in size than it's parent neutral atom.
Q.No.5. what is bond length.discuss it's significance.
Ans. Bond length is defined as the distance between the nuclei of two bonded atoms.
The length of given bond is it's stability. A molecule with small bond length is more stable than that with large bond length. The bond length can be used to infer the presence of pi-bonding in a molecule.
Q.No. 6 what is electron affinity?
Ans. It is defined as the amount of energy released , when a gaseous grounded state atom gains an electrons to form an anion.
Q. No.7 what is electronegativity?
Ans. When two different atoms in a molecule are bonded together by a covalent bond, the electron pair forming the covalent bond is not shared equally by both atoms. Rather, the electron pair lies nearer to one atom than the other. The relative tendency of the bonded atoms in a molecule to attract the shared electron pair towards itself is known as it's electronegativity.
Q.No.8 what is electropositivity?
Ans. Electropositivity is the converse of electronegativity. It is related to the tendency to lose electrons. The greater is the tendency to lose electron to form the cation, greater is the metallic or electropositive character.
Q.No.9. what is redox potential?
Ans. Redox potential is the measure of the tendency of an element or ion to gain or lose electrons.It is combined term involving reduction potential and oxidation potential.
Q.No.10.Define electrochemical series.
Ans. Electrochemical series of elements is the arrangements of elements in order of increasing or decreasing electrode potentials.
0 Comments
Thanks for visiting blog. if you have any query please let me know.