CBSE Class 11 Chemistry Classification Of Elements And Periodicity In Properties Assignment

Classification Of Elements And Periodicity In Properties MCQ Questions with Answers Class 11 Chemistry

Question- Newlands could classify elements only upto –
(a) copper
(b) chlorine
(c) calcium
(d) chromium
Answer-C

Question- Mendeleev classified elements in
(a) increasing order of atomic groups
(b) eight periods and eight groups
(c) seven periods and nine groups
(d) eight periods and seven groups
Answer-C

Question-If the two members of a Dobereiner triad are phosphorus and antimony, the third member of this triad is
(a) arsenic
(b) sulphur
(c) iodine
(d) calcium
Answer-A

Question-In 1800, only ....X.... elements were known. Here, X refers to
(a) 63
(b) 31
(c) 114
(d) 92
Answer-B

Question- The most significant contribution towards the development of periodic table was made by
(a) Mendeleev
(b) Avogadro
(c) Dalton
(d) Cavendish
Answer-A

Question-Periodic classification of elements is used to examine the
(a) periodic trends in physical properties of elements
(b) periodic trends in chemical properties of elements
(c) Both (a) and (b)
(d) None of the above
Answer-C

Question-At present, how many elements are known
(a) 110
(b) 112
(c) 113
(d) 118
Answer-D

Question-On which of the following Dobereiner’s Triad law is not applicable?
(a) Cl, Br, I
(b) Ca, Sr, B
(c) F, Cl, Br
(d) Li, Na, K
Answer-C

Question-According to Newlands theory, when elements are arranged in the order of increasing atomic weight which number element had similar properties to the first element.
(a) third
(b) seventh
(c) eighth
(d) sixth
Answer-C

Question-The law of triads is applicable to a group of
(a) Cl, Br, I
(b) C, N, O
(c) Na, K, Rb
(d) H, O, N
Answer-A

Question-Lothar Meyer plotted the physical properties such as atomic volume, melting point and ...X... against atomic weight. Here, X refers to
(a) mass
(b) boiling point
(c) surface tension
(d) None of these
Answer-B

Question- Cl, Br, I, if this is Dobereiner’s triad and the atomic masses of Cl and I are 35.5 and 127 respectively the atomic mass of Br is
(a) 162.5
(b) 91.5
(c) 81.25
(d) 45.625
Answer-C

Question-Noble gases were included in Mendeleev’s periodic table in the
(a) 1st group
(b) 7th group
(c) 8th group
(d) None of these
Answer-D

Question-Johann Doberiner gave the idea of trends among physical and ...X... of several groups of three elements. Here, X refers to
(a) atomic number
(b) atomic mass
(c) chemical properties
(d) None of these
Answer-C

Question-Select the correct chronological order for the discoveries of the following scientists.
Dobereiner, Newlands, Chancourtois, Mendeleev
(a) Chancourtois, Dobereiner, Newlands, Mendeleev
(b) Dobereiner, Chancourtois, Newlands, Mendeleev
(c) Dobereiner, Newlands, Chancourtois, Mendeleev
(d) Chancourtois, Newlands, Dobereiner, Mendeleev
Answer-B

Question- Who developed long form of the periodic table?
(a) Lothar Meyer
(b) Neils Bohr
(c) Mendeleev
(d) Moseley
Answer-B

Question- The incorrect statement among the following is :
(a) the first ionization energy of Al is less than first ionization energy of Mg.
(b) the second ionization energy of Mg is greater than second ionization energy of Na.
(c) the first ionization energy of Na is less than first ionization energy of Mg.
(d) the third ionization energy of Mg is greater than third ionization energy of Al.
Answer. B

Question- Assertion : F atom has a less negative electron affinity than Cl atom. 
Reason : Additional electrons are repelled more effectively by 3p electrons in Cl atom than by 2p electrons in F atom.
(a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are true, but Reason is not correct explanation of Assertion.
(c) Assertion is true but Reason is false.
(d) Assertion is false but Reason is true.
Answer. C

Question- The correct order of radii is : 
(a) N < Be < B
(b) F^– < O^2– < N^3–
(c) Na < Li < K
(d) Fe³⁺ < Fe²⁺ < Fe⁺⁴
Answer. B

Question- Assertion : The first ionization energy of Be is greater than that of B.
Reason : 2p orbital is lower in energy than 2s. 
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are true but Reason is not correct explanation of Assertion.
(c) Assertion is true but Reason is false.
(d) Assertion is false but Reason is true.
Answer. C

Question- The set representing the correct order of first ionization potential is : 
(a) K > Na > Li
(b) Be > Mg > Ca
(c) B > C > N
(d) Ge > Si > C
Answer. B

Question- Identify the least stable ion amongst the following :
(a) Li^–
(b) Be^–
(c) B^–
(d) C^–
Answer. B

Question-  Which one of the following ions has the highest value of ionic radius ? 
(a) Li⁺
(b) B³⁺
(c) O^2–
(d) F–
Answer. C

Question- In which of the following arrangements the order is NOT according to the property indicated against it ?
(a) Al³⁺ < Mg²⁺ < Na+ < F– – increasing ionic size
(b) B < C < N < O – increasing first ionisation enthalpy
(c) I < Br < F < Cl – increasing electron gain enthalpy (with negative sign)
(d) Li < Na < K < Rb – increasing metallic radius
Answer. B

Question- Which of the following factors may be regarded as the main cause of lanthanide contraction ?
(a) Greater shielding of 5d electrons by 4f electrons. 
(b) Poorer shielding of 5d electron by 4f electrons.
(c) Effective shielding of one of 4f electrons by another in the sub-shell.
(d) Poor shielding of one of 4f electron by another in the sub-shell.
Answer. B

Question- The lanthanide contraction is responsible for the fact that : 
(a) Zr and Y have about the same radius
(b) Zr and Nb have similar oxidation state
(c) Zr and Hf have about the same radius
(d) Zr and Zn have same oxidation state.
Answer. C

Question- The increasing order of the first ionization enthalpies of the elements B, P, S and F (lowest first) is :
(a) F < S < P < B
(b) P < S < B < F
(c) B < P < S < F
(d) B < S < P < F
Answer. D

Question- Lanthanoid contraction is caused due to : 
(a) the appreciable shielding on outer electrons by 4ƒ electrons from the nuclear charge
(b) the appreciable shielding on outer electrons by 5ƒ electrons from the nuclear charge
(c) the same effective nuclear charge from Ce to Lu
(d) the imperfect shielding on outer electrons by 4f electrons from the nuclear charge
Answer. D

Question- The set representing the correct order of ionic radius is : 
(a) Na⁺ > Li⁺ > Mg²⁺ > Be²⁺
(b) Li⁺ > Na⁺ > Mg²⁺ > Be²⁺
(c) Mg²⁺ > Be²⁺ > Li⁺ > Na⁺
(d) Li⁺ > Be²⁺ > Na⁺ > Mg²⁺
Answer. A

Question- The correct sequence which shows decreasing order of the ionic radii of the elements is :
(a) Al³⁺ > Mg²⁺ > Na⁺ > F^– > O^2–
(b) Na⁺ > Mg²⁺ > Al³⁺ > O^2– > F^–
(c) Na⁺ > F^– > Mg²⁺ > O^2– > Al³⁺
(d) O^2– > F^– > Na⁺ > Mg²⁺ > Al³⁺
Answer. D

Question- The correct order of electron gain enthalpy with negative sign of F, Cl, Br and I, having atomic number 9, 17, 35 and 53 respectively, is: 
(a) F > Cl > Br > I
(b) Cl > F > Br > I
(c) Br > Cl > I > F
(d) I > Br > Cl > F
Answer. B

Question- The increasing order of the ionic radii of the given isoelectronic species is : 
(a) Cl^–, Ca²⁺ , K⁺, S^2–
(b) S^2– , Cl^–, Ca²⁺, K⁺
(c) Ca²⁺, K⁺ , Cl^– , S^2–
(d) K⁺, S^2–, Ca²⁺ , Cl^–
Answer. C

Question- Which of the following represents the correct order of increasing first ionization enthalpy for Ca, Ba, S, Se and Ar ? 
(a) Ca < S < Ba < Se < Ar
(b) S < Se < Ca < Ba < Ar
(c) Ba < Ca < Se < S < Ar
(d) Ca < Ba < S < Se < Ar
Answer. C

Question- The ionic radii (in Å) of N^3–, O^2– and F^– are respectively :
(a) 1.36, 1.40 and 1.71
(b) 1.36, 1.71 and 1.40
(c) 1.71, 1.40 and 1.36
(d) 1.71, 1.36 and 1.40
Answer. C

ONE MARK QUESTIONS

1 Write the symbol and IUPAC name of the element with atomic number 117.
2 Arrange the following elements S,P,O,N in the increasing order of non-metallic character.
3 What are the various factors due to which the ionization enthalpy of the main group elements tends to increase across a period.
4 What do you mean by screening effect.
5 To which group and period will the element with atomic number 111 belong?
6 What is the oxidation state and covalency of [Al Br(NH₃)₅]²⁺
7 What are
i.) d block elements ii. ) f block elements?

TWO MARKS QUESTIONS

1 Predict the position in the periodic table a) (n-1)d¹ ns² where n=4 b) (n-1) d² ns² where n=5
2 The first &second ionization enthalpies &electron gain enthalpies of elements A,B,C.&D are as follows

Identify the element which is likely to be
i) A most reactive non-metal ii) A most reactive metal
iii) a noble gas iv) metal forming binary halide (MX₂)
3 What are isoelectronic species? Name the species that will be iso electronic with each of the
following atoms or ions. (i) F- (ii) Ar (iii) Mg²⁺ (iv) Rb⁺
4 What is the difference between electron gain enthalpy and electro negativity?
5 Explain why cations are smaller than corresponding anions.
6 Write the general outer electronic configuration of
i. s block elementsii. p block elements
iii. d block elements iv. f block elements

THREE MARKS QUESTIONS

1. Arrange the following in increasing order of size by giving reason
a) K, K⁺
b) I⁺, I , I^-
c) Li⁺, Na⁺
d) Mg²⁺, Na⁺

2. If A = 1s², 2s², 2p1
B = 1s², 2s², 2p⁶, 3s², 3p¹
C = 1s², 2s², 2p⁶, 3s², 3p³
D = 1s², 2s², 2p⁶, 3s², 3p⁵
E = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s²
F = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹
a) Which is the most metallic?
b) Which has the highest negative value for electron gain enthalpy?
c) Which one belongs to the d-block?
d) Which is a halogen?
e) Which two elements are in the same group?
f) Which elements belongs to the 13th group?

3. Give reason.
a) Cl- is larger than Cl.
b) IE₂ of Na is greater than IE₂ of Mg.
c) IE₁ of B is 800kJ/mole while IE₁ of Be is 900kJ/mole.

4. Justify the following
a) Lanthanides and actinides are placed separately in the periodic table
b) IE of Na+ is almost double that of Ne.
c) Third period contains only 8 elements

5. Explain why?
a) Δ_egH of F is less negative than that of Cl.
b) IE1 of N is 1402kJ while that of O is 1314kJ.
c) Li & Mg resemble in many of their properties

6 Which atom in each of the following pairs has greater first IE?
a) B or C
b) N or O
c) F or Ne
d) Cl or F
e) K or Ar
f) Kr or Xe