MCQ on Periodic Classification of Elements

All of the matter in our environment is composed of fundamental building blocks known as elements. Initially, only 31 chemical elements were discovered in 1800, according to historical records. In 1865, a technological breakthrough resulted in the discovery of approximately 63 additional elements. The periodic classification of elements became necessary as a result of this.

At the moment, we are aware of 118 different elements. Some of the 118 chemical elements are created by humans, while others are naturally occurring.

1. The Newlands relation is referred to as 

a) the Musical Law, 

b) the Law of Octaves,

c) the Periodic Law,

d) the Atomic Mass Law.

Answer: b is the correct answer.

A generalisation made by the English chemist J.A.R. Newlands in 1865 that, if the chemical elements are arranged according to increasing atomic weight, those with similar physical and chemical properties will appear after each interval of seven elements, which is a generalisation of the law of octaves.

2. Until what element was the Law of Octaves determined to be applicable?

a) Calcium, 

b) Cobalt

c) Potassium 

d) Aluminium

Answer: b is the correct answer.

The Law of Octaves was only valid up to the element calcium, because beyond calcium, every eighth element did not have properties that are identical to those of the first element.

3. Gaps were left in Mendeleev’s Periodic Table to allow for the discovery of new elements in the future. Which of the following elements did not find a place in the Periodic Table until much later in history?

a) Silicon

b) Oxygen

c) Fluorine

d) Germanium

Answer: d is the answer to the question.

Mendeleev himself added these elements to the periodic chart in 1902 as group 0 elements, without altering the fundamental principle of the periodic table in the process. Alfred Werner, a Swiss chemist, was the first to solve the dead zone of Mendeleev’s table, which was discovered in 1905. He came to the conclusion that the rare-earth elements (lanthanides), of which there were 13 known, were contained within that gap.

4. The qualities of eka-aluminium predicted by Mendeleev are the same as the properties of the element aluminium, which was discovered later.

a) scandium

b) germanium

c) Gallium

d) Aluminium

e) Zinc

Answer: c is the correct answer.

Eka-aluminium and gallium are the same elements because the properties of Eka-Aluminium are almost identical to the qualities of the gallium element. Eka-Aluminium is a chemical element that has nearly identical properties to the gallium element. The properties of the elements, such as their atomic mass, density, melting temperature, the formula of chloride, and the formula of oxide, are nearly identical to those anticipated by Mendeleev in his theory.

5. An atom of an element has the electrical configuration 2,8 when it is in its pure state. Is it a member of any particular group?

a) The fourth group

b) The sixth group

c) 18th group

d) 15th group

Answer: c is the answer to the question.

Group number eighteen. This suggests the presence of a noble gas element. Noble gas elements are found in Group 18 of the modern periodic table, which is the most recent revision. Thus, the element having electronic configuration 2, 8 would be found in group 18 of the Modern Periodic Table, according to this definition. Therefore, option (C) is the most appropriate choice.

6. The arrangement of elements in the Modern Periodic Table is based on their\s

a) rising atomic mass in the period\s

b) increasing atomic number in the horizontal rows

c) increasing atomic number in the vertical columns

d) increasing atomic mass in the group

Answer: b is the correct answer.

The elements are listed in ascending order of atomic numbers, with heavier elements at the top of the list. The horizontal rows of the periodic table are referred to as Periods, and the vertical columns of the periodic table are referred to as Groups. The elements in the Modern Periodic Table are divided into seven Periods and eighteen Groups, as shown in the diagram below. The chemical elements are arranged from left to right and top to bottom in order of increasing atomic number, or the number of protons in an atom’s nucleus, which generally corresponds to increasing atomic mass. The elements are arranged from left to right and top to bottom in order of increasing atomic mass.

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

a) Group 8

b) Group 2

c) Group 18

d) Group 10

c is the correct answer.

This suggests the presence of a noble gas element. Noble gas elements are found in Group 18 of the modern periodic table, which is the most recent revision. Thus, the element having electronic configuration 2, 8 would be found in group 18 of the Modern Periodic Table, according to this definition. Therefore, option (C) is the most appropriate choice.

8. Element ‘X’ creates a chloride with the formula XCl2, which is a solid with high melting point. X would most likely be in the same group of the periodic table as:

a) Si

b) Mg

c) Al

d) Na

Answer: b is the correct answer.

Since Mg has the valency of 2, and the valency of a group remains constant… Aside from that, when it reacts with Chlorine (which has valency 1), it creates MgCl2.

Na has a valency of one.

Al has a valency of three.

Si has a valency of four.

9. Which of these belong to the same period?

Element A B C

Atomic number 2 10 5 respectively.

a) A, B 

b) B, C

c) C, A

d) A, B and C

Answer: b)Explanation: Reason. B= 10 (2, 8), C = 5 (2, 3) (2, 3) Both have 2 periods.

10. Which one of the following statements is not correct concerning the trends in the properties of the elements of a period on travelling from left to right?

a) The oxides become more acidic

b) The elements become less metallic

c) There is an increase in the amount of valence electrons

d) The atoms shed their electrons more easily

Answer: d is the answer to the question

11. The atom of an element has electronic con-figuration 2, 8, 7. To which of the following elements would it be chemically similar?

a) N(7)

b) P(15)

c) Na(11)

d) F (9)

Answer: d

Explanation: Reason. Both have similar numbers of valence electrons.