VBQs Class 10 Science Periodic Classification of Elements

Please refer to VBQs for Class 10 Science Periodic Classification of Elements. All value based questions for English Class 10 have been provided with solutions. We have provided below important values questions and answers. Students should learn these solved VBQs for Class 10 Science as these will help them to gain more marks and help improve understanding of important topics.

Periodic Classification of Elements VBQs Class 10 Science with Answers

Multiple Choice Questions

Question. Which of the following statement(s) about the Modern Periodic Table are incorrect
(i) The elements in the Modern Periodic Table are arranged on the basis of their decreasing atomic number
(ii) The elements in the Modern Periodic Table are arranged on the basis of their increasing atomic masses
(iii) Isotopes are placed in adjoining group (s) in the Periodic Table
(iv) The elements in the Modern Periodic Table are arranged on the basis of their increasing atomic number
(a) (i) only
(b)(i), (ii) and (iii)
(c) (i), (ii) and (iv)
(d) (iv) only

Question. On the basis of electronic configuration of 5X, the group number and period of the element ‘X’ is:
(a) Group 15 period 2
(b) Group 13 period 2
(c) Group 19 period 5
(d) Group 13 period 5

Question. Three elements B, Si and Ge are
(a) metals
(b) non-metals
(c) metalloids
(d) metal, non-metal and metalloid respectively

Question. Which of the given elements A, B, C, D and E with atomic number 2, 3, 7, 10 and 30 respectively belong to the same period?
(a) A, B, C
(b) B, C, D
(c) A, D, E
(d) B, D, E

Question. What is the atomic number of element of period 3 and group 17 of the Periodic Table?
(a) 10
(b) 4
(c) 17
(d) 21

Question. An element X from group 2 of the Periodic Table reacts with Y from group 17 to form a compound. Give the formula of the compound.
(a) XY₂
(b) XY
(c) X₂Y
(d) (XY)₂

Question. Where would you locate the element with electronic configuration 2, 8 in the Modern Periodic Table?
(a) Group 8
(b) Group 2
(c) Group 18
(d) Group 10

Question. Newlands relation is called
(a) Musical Law
(b) Law of Octaves
(c) Periodic Law
(d) Atomic Mass Law

Question. An element ‘X’ is forming an acidic oxide. Its position in modern periodic table will be
(a) Group 1 and Period 3
(b) Group 2 and Period 3
(c) Group 13 and Period 3
(d) Group 16 and Period 3

Question. Elements P, Q, R and S have atomic numbers 11, 15, 17 and 18 respectively. Which of them are reactive non-metals?
(a) P and Q
(b) P and R
(c) Q and R
(d) R and S

Assertion Reason type Questions

Question. Assertion: Elements in the same vertical column have similar properties.
Reason: The properties of elements are periodic functions of their atomic numbers.

Question. Assertion: Isotopes of an element were given separate places in Mendeleev’s periodic table.
Reason: Isotopes of an element have different atomic masses.

Question. Assertion : Atomic size decreases along a period.
Reason : Effective nuclear charge decreases as the atomic number increases resulting in the increased attraction of electrons to the nucleus.

Question. Assertion : In Mendeléev Periodic Table, cobalt was placed before nickel.
Reason : The atomic mass of cobalt is less than nickel

Question. Assertion: Fluorine is more reactive than Chlorine.
Reason: The chemical reactivity of non-metals increases down the group.

Case based Questions

Atoms of eight elements A, B, C, D, E, F, G and H have the same number of shells but
different number of electrons in their outermost shell. It was found that elements A and G combine
to form an ionic compound. This compound is added in a small amount to almost all vegetable
dishes during cooking. Oxides of elements A and B are basic in nature while those of E and F are
acidic. The oxide of D is almost neutral.

Based on the above information answer the following questions:

Question. To which group or period of the Periodic Table do the listed elements belong?
Answer. A and B belong to group 1 and 2 because they form basic oxides.
C belongs to group 13 as it has 3 valence electrons.
D belongs to group 14 as it forms almost neutral oxide.
E and F belong to group 15 and 16 as they form acidic oxides,
G belongs to group 17 as it has 7 valence electrons and H belongs to group 18
They belong to 3rd period of the Periodic Table because AG is NaCl, added in a small amount to almost all vegetable dishes during cooking and Na and Cl belong to 3rd period.

Question. What would be the nature of compound formed by a combination of elements B and F?
Answer. Ionic compounds will be formed because ‘B’ is metal and ‘F’ is non-metal. ‘B’ can lose two electrons and ‘F’ can gain two electrons.

Question. Which two of these elements could definitely be metals?
Answer. A and B are definitely metals as they form basic oxides.

Question. Which one of the eight elements is most likely to be found in gaseous ,state at room temperature?
Answer. G and H are gaseous at room temperature.

Question. If the number of electrons in the outermost shell of elements C and G be 3 and 7 respectively, write the formula of the compound formed by the combination of C and G.
Answer. CG3 is the formula of the compound formed by combination of C and G.

Descriptive Questions Of 1 Mark

Question. What is the basis for arrangement of elements in the Mendeleev periodic table?
Answer. Increasing order of atomic mass and similarity in chemical properties

Question. Name the two elements for which temporary names were given as Eka-aluminium and Eka-silicon and spaces were left by Mendeleev in his table even before their discovery.
Answer. Gallium and Germanium

Question. If Lithium, sodium and potassium form a Dobereiner’s triad, and if the atomic masses of Li and K are 7 and 39, respectively, Predict the atomic mass of sodium?
Answer. Sum of atomic masses of extreme elements=7+39 = 46. Average at mass =46/2 = 23.So sodium
will have atomic mass = 23

Question. State Mendeleev periodic law
Answer. Properties of elements are a periodic function of their atomic masses.

Question. Write the number of groups or vertical columns and periods or horizontal rows in the modern periodic table.
Answer. There are 18 vertical columns or groups and seven horizontal rows or periods in the modern periodic table.

Short Answer Type Questions

Question. The elements of the second period of the Periodic Table are given below: Li Be B C N O F
(a) Give reason to explain why atomic radii decrease from Li to F.
(b) Identify the most (i) metallic and (ii)non-metallic element.
Answer. (a) It is because nuclear charge increases due to increase in atomic number, therefore, force of Attraction between nucleus and valence electrons increases, i.e. effective nuclear charge increases, hence atomic radii decrease from Li to F.
(b) (i) Most metallic element is ‘Li’ as it can lose electrons easily due to larger atomic size.
(ii) Most non-metallic element is ‘F’ because it can gain electrons easily due to smallest atomic size.

Question. (a). On moving from left to right in the second period when happens to the number of valence electrons?
(b). How does reactivity of metals vary down a group?
Answer. a. Number of valence electrons increases from left to right in the second period
b. Reactivity of metals goes on increasing down a group.

Question. Mention three achievements of Mendeleev’s periodic table and one defect.
Answer. Merits (a) It could classify all the elements discovered at that time.
(b) It helped in discovery of new elements.
(c) It helped in correction of atomic mass of some of the elements.
Defect;1. All isotopes of an element do not find position in this table.

Question. The elements of the third period of the Periodic Table are given below:
Na, Mg, Al, Si, P,S, Cl, Ar
(a) Which atom is bigger, Na or Mg? Why?
(b) Identify the most (i) metallic and (ii) non-metallic element in Period 3.
Answer. (a) Sodium is bigger than magnesium as it has lesser nuclear charge so there is less force of attraction between nucleus and valence electrons and less effective nuclear charge. It is, therefore, bigger in size.
(b) (i) Sodium is the most metallic as it can lose electrons easily due to its larger atomic size,
(ii) Chlorine is the most non-metallic element because it can gain electrons easily due to its
smallest atomic size.

Question.(a). How does the electronic configuration of an atom of an element related to its position in the modern periodic table? Explain with one example.
(b) Find the group and period of element with Z = 12?
Answer. (a) The position of element depends upon number of valence electrons which depend upon electronic configuration. Those elements which have same valence electrons, occupy same group.
Eg; those elements which have one valence electron belong to group 1. Elements with two valence electrons belong to group 2. Period number is equal to number of shells. If valence electrons are equal to 1, it belongs to group 1. If it has 2 shells, it belongs to second period, e.g. if element ‘X’ has atomic number 11, its electronic configuration is 2, 8,1. It has one valence electron, it belongs to group 1 and it has three shells therefore, it is in third period.
(b) Z = 12 and the configuration is 2,8,2So it should belong to 2 nd group and 3^rd period

Long Answer Type Questions

Question. a) In this ladder (Figure 5.2) symbols of elements are jumbled up. Rearrange these symbols of elements in the increasing order of their atomic number in the Periodic Table.
(b) Arrange them in the order of their group also.

Answer.

(a) H, He, Li, Be, B, C, N, O, F, Ne, Mg, Al, Si, P, S, Cl, Ar, K, Ca
(b) Group 1:H, Li, Na, K
Group 2: Be, Mg, Ca
Group 13: B. Al
Group 14: C, Si
Group 15: N. P
Group 16: 0, S
Group 17: F. U
Group 18: He, Ne, Ar

Question. Mendeleev ′ predicted the existence of certain elements not known at that time and named two of them as Eka-silicon and Eka-aluminum.
(a) Name the elements which have taken the place of these elements
(b) Mention the group and the period of these elements in the Modern Periodic Table.
(c) Classify these elements as metals, non-metals or metalloids
(d) How many valence electrons are present in each one of them?
Answer. (a) Eka- silicon is Germanium (Ge)
Eka- aluminium is Gallium (Ga)
(b) Eka- silicon – group 14 & period 3
Eka- aluminium – Group 13 & period 3
(c) Eka- silicon – metalloid
Eka- aluminium – metal
(d) Valence electron present in Eka- silicon is 4
Valence electron present in Eka- aluminium is 3

Question. From the part of the periodic table given, answer the following questions.

(a)Which is the most reactive metal?
(b) Name the family of L, Q, R, T.
(c) Name one element of group 2 and 15,
(d) Name one member of group 18 other than neon.
(e) Give the name of the element S placed below carbon in group 14.
Answer. (a) The element Z is the most reactive metal.
(b) The elements are present in group 17. The family is that of halogens.
(c) One element belonging to group 2 is calcium (Ca) while one present in group 15 is nitrogen (N).
(d) The element argon (Ar) is also present in group 18.
(e) The element is silicon (Si)