5. Periodic Classification of Elements

SEBA Class 10 Science Chapter 5. Periodic Classification of Elements

Chapter 5. Periodic Classification of Elements

SEBA Class 10 Chapter 5 Periodic Classification of Elements Multiple Choice Questions and answers

Question : Which of the following statements is not a correct statement about the trends when going from left to right across the periods of periodic Table. [SEBA 2018]

(a) The elements become less metallic in nature.

(b) The number of valence electrons increases.

(d) The oxides become more acidic.

Answer : (b) The number of valence electrons increases.

2. Element X forms a chloride with the formula , which is a solid with a high melting point. X would most likely be in the same group of the Periodic Table as [SEBA 2019]

(a) Na (b) Mg (c) AI (d) Si

Answer : (b) Mg

Question : In the periodic table of the elements, in a period from left to right atomic radius gradually :[SEBA 2016]

(a) increases (b) decreases (c) remain same (d) none of the above

Answer : (b) decreases.

[ In the periodic table of elements, as you move from left to right across a period, the atomic radius generally decreases. Therefore, the correct answer is (b) decreases. ]

Question : An atom has electronic configuration 2,8,7 . To which of the following elements would it be chemically, similar ? (atomic numbers are given in the parentheses ) [SEBA 2017,2020]

(a) N(7) (b) F(9) (c) P(15) (d) Ar(18)

Answer : (b) F(9)

[Electronic configuration of N is 2.5

Electronic configuration of F is 2.7

Electronic configuration of P is 2.8.5

Electronic configuration of Ar is 2.8.8 ]

Question : Using Mendeleev’s Periodic Table the formula predicted for the oxide of element ‘K’ is :[SEBA2021]

(a) (b) (c) (d)

Answer : (b)

Question : Which of the following is not an example of metalloid ? [2023]

(a) Si (b) Ge (c) B (d) Al

Answer : (d) Al

Question : Upto which element, the Law of Octaves was found to be applicable

(a) Oxygen

(b) Calcium

(d) Potassium

Answer : (b) Calcium

[ The Law of Octaves was a periodic law formulated by John Newlands in the 19th century, which attempted to organize the known chemical elements at the time. According to this law, every eighth element displayed similar properties. The law was found to be applicable up to calcium. ]

Question : According to Mendeleev's′ Periodic Law, the elements were arranged in the periodic table in the order of

(a) increasing atomic number

(b) decreasing atomic number

(d) decreasing atomic masses

Answer : (c) increasing atomic masses

[ According to Mendeleev's Periodic Law, the elements were arranged in the periodic table in the order of (c) increasing atomic masses. Mendeleev's periodic table was based on the increasing atomic masses of elements, and he organized the elements in rows and columns based on their chemical and physical properties.]

Question : In Mendeleev′ ’s Periodic Table, gaps were left for the elements to be discovered later. Which of the following elements found a place in the perioidc table later

(a) Germanium

(b) Chlorine

(d) Silicon

Answer : (a) Germanium

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)

Answer : (b) (i), (ii), and (iii)

[The correct statement about the Modern Periodic Table is (iv) The elements in the Modern Periodic Table are arranged on the basis of their increasing atomic number. ]

Question : Which of the following statements about the Modern Periodic Table is correct:

(a) It has 18 horizontal rows known as Periods

(b) It has 7 vertical columns known as Periods

(d) It has 7 horizontal rows known as Groups

Answer : (c) It has 18 vertical columns known as Groups.

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

(d) B, D, E

Answer : (b) B, C, D

[ The elements with atomic numbers 2, 3, 7, 10, and 30 are Helium (He), Lithium (Li), Nitrogen (N), Neon (Ne), and Zinc (Zn) respectively. These elements actually belong to the same period (period 2) in the periodic table. ]

Question : The elements A, B, C, D and E have atomic number 9, 11, 17, 12 and 13 respectively. Which pair of elements belong to the same group?

(a) A and B

(b) B and D

(d) D and E

Answer : (c) A and C

[ The elements in the same group have similar chemical properties, and elements in the same group have the same number of valence electrons. In this case, elements A and C have atomic numbers 9 and 17, respectively. Both of these elements belong to Group 17 (also known as Group VIIA or the halogens) because they have the same number of valence electrons.]

Question : Where would you locate the element with electronic configuration 2,8 in the Modern Periodic Table?

(a) Group 8

(b) Group 2

(d) Group 10

Answer : (c) Group 18

[ The electronic configuration 2,8 corresponds to the configuration of a noble gas. In this case, it is the electronic configuration of neon (Ne). In the Modern Periodic Table, noble gases are found in Group 18. ]

Question : An element which is an essential constituent of all organic compounds belongs to

(a) group 1

(b) group 14

(d) group 16

Answer : (b) Group 14

[ An element which is an essential constituent of all organic compounds is carbon. Carbon belongs to Group 14 in the Modern Periodic Table. ]

Question : Which of the following is the outermost shell for elements of period 2?

(a) K shell

(b) L shell

(d) N shell

Answer : (b) L shell

[ In the Modern Periodic Table, elements of period 2 have electrons filling the first and second shells. The outermost shell for elements of period 2 is the second shell. The second shell is denoted by the letter (b) L shell. ]

Question : Which one of the following elements exhibit maximum number of valence electrons?

(a) Na

(b) Al

(d) P

Answer : (d) P (Phosphorus) with 5 valence electrons.

[ Valence electrons are the electrons in the outermost shell of an atom. The number of valence electrons increases as you move from left to right across a period in the periodic table.

Sodium (Na) is in Group 1 and has 1 valence electron.

Aluminum (Al) is in Group 13 and has 3 valence electrons.

Silicon (Si) is in Group 14 and has 4 valence electrons.

Phosphorus (P) is in Group 15 and has 5 valence electrons. ]

Question : Which of the following gives the correct increasing order of the atomic radii of O, F and N ?

(a) O, F, N

(b) N, F, O

(d) F, O, N

Answer : (d) F, O, N

[ The atomic radii generally decrease across a period from left to right on the periodic table. Among the given elements (Oxygen, Fluorine, and Nitrogen), they are in the same period (Period 2). ]

Question : Which among the following elements has the largest atomic radii?

(a) Na

(b) Mg

(d) Ca

Answer : (c) K (Potassium)

[ Atomic radius generally increases down a group in the periodic table. The elements provided (Na, Mg, K, Ca) are all in the same group (Group 2). The element with the largest atomic radius is at the bottom of the group. ]

Question : Which of the following elements would lose an electron easily?

(a) Mg

(b) Na

(d) Ca

Answer : (c) K (Potassium)

[ Elements in Group 1 (alkali metals), such as potassium, have one electron in their outermost shell, making it easier for them to lose that electron and achieve a stable electron configuration.]

Question : Which of the following elements does not lose an electron easily?

(a) Na

(b) F

(d) Al

Answer : (b) F (Fluorine)

[ Fluorine belongs to Group 17 (halogens), and it has a tendency to gain electrons rather than lose them. Elements in this group typically have high electronegativity and are more likely to accept electrons to achieve a stable electron configuration.]

Question : Which of the following are the characteristics of isotopes of an element?

(i) Isotopes of an element have same atomic masses

(ii) Isotopes of an element have same atomic number

(iii) Isotopes of an element show same physical properties

(iv) Isotopes of an element show same chemical properties

(a) (i), (iii) and (iv) (b) (ii), (iii) and (iv)

Answer : (d) (ii) and (iv)

[ The characteristics of isotopes of an element are: (i) Isotopes of an element have the same atomic number. (ii) Isotopes of an element have different atomic masses. (iii) Isotopes of an element show the same chemical properties. (iv) Isotopes of an element may have slightly different physical properties.]

Question : Arrange the following elements in the order of their decreasing metallic character

Na, Si, Cl, Mg, Al

(a) Cl > Si >Al > Mg >Na

(b) Na >Mg >Al >Si > Cl

(d) Al > Na> Si > Ca> Mg

Answer : (b) Na > Mg > Al > Si > Cl

Question : Arrange the following elements in the order of their increasing non-metallic character

Li, O, C, Be, F

(a) F < O < C < Be < Li

(b) Li < Be < C < O< F

(d) F < O < Be < C < Li

Answer : (d) F < O < Be < C < Li

Question : What type of oxide would Eka– aluminium form?

(a)

(b)

(c)

(d) EO

Answer : (c)

[ Eka-aluminium refers to the element gallium (Ga). Gallium is located below aluminium (Al) in the periodic table. The general formula for the oxide of gallium is . ]

Question : Three elements B, Si and Ge are

(a) metals

(b) non-metals

(d) metal, non-metal and metalloid respectively

Answer : (c) metalloids

[ The elements Boron (B), Silicon (Si), and Germanium (Ge) are metalloids. Metalloids have properties intermediate between metals and non-metals.]

Question : Which of the following elements will form an acidic oxide?

(a) An element with atomic number 7

(b) An element with atomic number 3

(d) An element with atomic number 19

Answer : (a) An element with atomic number 7 .

[ An acidic oxide is formed by a non-metallic element. Non-metals generally form acidic oxides.]

Question : The element with atomic number 14 is hard and forms acidic oxide and a covalent halide. To which of the following categories does the element belong?

(a) Metal

(b) Metalloid

(d) Left-hand side element

Answer : (b) Metalloid

[ The element with atomic number 14 is silicon (Si). Silicon is a metalloid. Metalloids exhibit properties that are intermediate between metals and non-metals.]

Question : Which one of the following depict the correct representation of atomic radius(r) of an atom?

(i) (ii)

(iii) (iv)

(a) (i) and (ii) (b) (ii) and (iii)

Answer : (b) (ii) and (iii)

Question : Which one of the following does not increase while moving down the group of the periodic table?

(a) Atomic radius

(b) Metallic character

(d) Number of shells in an element

Answer : (c) Valence

[ The property that does not increase while moving down a group of the periodic table is valence . ]

Question : On moving from left to right in a period in the periodic table, the size of the atom.

(a) increases

(b) decreases

(d) first decreases and then increases

Answer : (b) decreases

[ This is due to the increase in effective nuclear charge, which attracts the electrons more strongly, leading to a decrease in atomic size.]

Question : Which of the following set of elements is written in order of their increasing metallic character?

(a) Be Mg Ca

(b) Na Li K

(d) C O N

Answer : (a) Be < Mg < Ca