Class 11 Chemistry - Chapter Classification of Elements and Periodicity in Properties NCERT Solutions | What does atomic radius and ionic
What does atomic radius and ionic radius really mean to you?
Atomic radius and ionic radius are the periodic properties which are directly or indirectly related to the electronic configuration of their atoms and shows gradation on moving down a group or along a period.
Atomic radius is defined as the distance from the centre of the nucleus to the outer most shell containing the electrons. It measures the size of an atom. It is of 3 types:
A) Covalent radius- It is the one half of the distance between the centres of the nuclei of two adjacent similar atoms joined to each other by single covalent bond.
Covalent radius = inter nuclear distance in the bonded atoms/ 2
B) Metallic radius- It is defined as half the distance between the centres of the nuclei of two adjacent atoms in the metallic crystal.
C) Van der waal’s radius- It is defined as one half of the inter nuclear distance between 2 similar adjacent atoms belonging to the two neighbouring molecules of the same substance in the solid state.
Ionic radius means the radius of an ion (cation or anion). It is defined as the distance from the centre of the nucleus of the ion upto which it exerts its influence on the electron cloud. The ionic radii can be calculated by measuring the distances between the cations and anions in ionic crystals.
Since a cation is formed by removing an electron from an atom, the cation has fewer electrons than the parent atom resulting in an increase in the effective nuclear charge. Thus, a cation is smaller than the parent atom. For example, the ionic radius of Na+ ion is 95 pm, whereas the atomic radius of Na atom is 186 pm. On the other hand, an anion is larger in size than its parent atom. This is because an anion has the same nuclear charge, but more electrons than the parent atom resulting in an increased repulsion among the electrons and a decrease in the effective nuclear charge. For example, the ionic radius of F– ion is 136 pm, whereas the atomic radius of F atom is 64 pm.
More Questions From Class 11 Chemistry - Chapter Classification of Elements and Periodicity in Properties
- Q:-
Write the general outer electronic configuration of s-, p-, d- and f- block elements.
- Q:-
Considering the elements B, Al, Mg, and K, the correct order of their metallic character is:
(a) B > Al > Mg > K
(b) Al > Mg > B > K
(c) Mg > Al > K > B
(d) K > Mg > Al > B - Q:-
What do you understand by isoelectronic species? Name a species that will be isoelectronic with each of the following atoms or ions.
(i) F–
(ii) Ar
(iii) Mg2+
(iv) Rb+
- Q:-
What is the basic difference between the terms electron gain enthalpy and electronegativity?
- Q:-
Considering the elements B, C, N, F, and Si, the correct order of their non-metallic character is:
(a) B > C > Si > N > F
b) Si > C > B > N > F
(c) F > N > C > B > Si
d) F > N > C > Si > B - Q:-
Assign the position of the element having outer electronic configuration
(i) ns2 np4 for n = 3 (ii) (n - 1)d2 ns2 for n = 4, and (iii) (n - 2) f7 (n - 1)d1 ns2 for n = 6, in the periodic table.
- Q:-
How does atomic radius vary in a period and in a group? How do you explain the variation?
- Q:-
Use the periodic table to answer the following questions.
(a) Identify an element with five electrons in the outer subshell.
(b) Identify an element that would tend to lose two electrons.
(c) Identify an element that would tend to gain two electrons.
(d) Identify the group having metal, non-metal, liquid as well as gas at the room temperature. - Q:-
Considering the elements F, Cl, O and N, the correct order of their chemical reactivity in terms of oxidizing property is:
(a) F > Cl > O > N
(b) F > O > Cl > N
(c) Cl > F > O > N
(d) O > F > N > Cl - Q:-
On the basis of quantum numbers, justify that the sixth period of the periodic table should have 32 elements.
Popular Questions of Class 11 Chemistry
- Q:-
How do you account for the formation of ethane during chlorination of methane?
- Q:-
What are hybridisation states of each carbon atom in the following compounds ?
(i) CH2=C=O,
(ii) CH3CH=CH2,
(iii) (CH3)2CO,
(iv) CH2=CHCN,
(v) C6H6
- Q:-
What will be the minimum pressure required to compress 500 dm3 of air at 1 bar to 200 dm3 at 30°C?
- Q:-
What are the common physical and chemical features of alkali metals?
- Q:-
Calculate the molecular mass of the following:
(i) H2O
(ii) CO2
(iii) CH4 - Q:-
Assign oxidation number to the underlined elements in each of the following species:
(a) NaH2PO4
(b) NaHSO4
(c) H4P2O7
(d) K2MnO4
(e) CaO2
(f) NaBH4
(g) H2S2O7
(h) KAl(SO4)2.12 H2O
- Q:-
Explain the formation of a chemical bond.
- Q:-
Choose the correct answer. A thermodynamic state function is a quantity
(i) used to determine heat changes
(ii) whose value is independent of path
(iii) used to determine pressure volume work
(iv) whose value depends on temperature only. - Q:-
A liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.
a) What is the initial effect of the change on vapour pressure?
b) How do rates of evaporation and condensation change initially?
c) What happens when equilibrium is restored finally and what will be the final vapour pressure? - Q:-
Justify the position of hydrogen in the periodic table on the basis of its electronic configuration.
Recently Viewed Questions of Class 11 Chemistry
- Q:-
Arrange the following metals in the order in which they displace each other from the solution of their salts.
Al, Cu, Fe, Mg and Zn.
- Q:-
Use the data given in the following table to calculate the molar mass of naturally occurring argon isotopes:
Isotope
Isotopic molar mass
Abundance
36Ar
35.96755 gmol–1
0.337%
38Ar
37.96272 gmol–1
0.063%
40Ar
39.9624 gmol–1
99.600%
- Q:-
State as to why
(a) a solution of Na2CO3 is alkaline ?
(b) alkali metals are prepared by electrolysis of their fused chlorides ?
(c) sodium is found to be more useful than potassium ?
- Q:-
How will you convert benzene into
(i) p - nitrobromobenzene
(ii) m - nitrochlorobenzene
(iii) p - nitrotoluene
(iv) acetophenone?
- Q:-
Explain with the help of suitable example polar covalent bond.
- Q:-
How many neutrons and protons are there in the following nuclei?
- Q:-
An atom of an element contains 29 electrons and 35 neutrons.
Deduce (i) the number of protons and (ii) the electronic configuration of the element. - Q:-
(i) Calculate the number of electrons which will together weigh one gram.
(ii) Calculate the mass and charge of one mole of electrons. - Q:-
The ejection of the photoelectron from the silver metal in the photoelectric effect experiment can be stopped by applying the voltage of 0.35 V when the radiation 256.7 nm is used. Calculate the work function for silver metal.
- Q:-
A 0.02 M solution of pyridinium hydrochloride has pH = 3.44. Calculate the ionization constant of pyridine
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