Question

Match the atomic numbers of the elements given in column I with the periods given in column II and mark the appropriate choice. \begin{tabular}{|c|c|c|c|} \hline \multicolumn{2}{|c|} { Column I (Atomic number) } & \multicolumn{2}{c|} { Column II (Period) } \\ \hline (A) & 31 & (i) & 5 \\ \hline (B) & 50 & (ii) & 3 \\ \hline (C) & 56 & (iii) & 4 \\ \hline (D) & 14 & (iv) & 6 \\ \hline \end{tabular} (a) (A) \(\rightarrow\) (i), (B) \(\rightarrow\) (ii), (C) \(\rightarrow\) (iii), (D) \(\rightarrow\) (iv) (b) (A) \(\rightarrow\) (ii), (B) \(\rightarrow\) (i), (C) \(\rightarrow(\mathrm{iv}),(\mathrm{D}) \rightarrow\) (iii) (c) (A) \(\rightarrow\) (iii), (B) \(\rightarrow(\mathrm{iv}),(\mathrm{C}) \rightarrow\) (i), (D) \(\rightarrow\) (ii) (d) (A) \(\rightarrow\) (iii), (B) \(\rightarrow\) (i), (C) \(\rightarrow\) (iv), (D) \(\rightarrow\) (ii)

Short answer

The correct match is option (d): (A) -> (iii), (B) -> (i), (C) -> (iv), (D) -> (ii).

Step-by-step solution

Identify the Period of Element A

Using the periodic table, determine the period of the element with atomic number 31, which is Gallium (Ga). Gallium is in the 4th period.

Identify the Period of Element B

Using the periodic table, determine the period of the element with atomic number 50, which is Tin (Sn). Tin is in the 5th period.

Identify the Period of Element C

Using the periodic table, determine the period of the element with atomic number 56, which is Barium (Ba). Barium is in the 6th period.

Identify the Period of Element D

Using the periodic table, determine the period of the element with atomic number 14, which is Silicon (Si). Silicon is in the 3rd period.

Match the Elements to the Correct Periods

Match the elements from column I with the correct periods in column II based on their atomic numbers: (A) 31 to period 4, (B) 50 to period 5, (C) 56 to period 6, and (D) 14 to period 3.

Select the Correct Option

Based on the matching, the correct option is (d) (A) \(\rightarrow\) (iii), (B) \(\rightarrow\) (i), (C) \(\rightarrow\) (iv), (D) \(\rightarrow\) (ii). This option correctly matches each element to its period.

Key concepts

Atomic Number

The atomic number of an element is a fundamental concept in chemistry, representing the number of protons in the nucleus of an atom of the element. Every chemical element is uniquely defined by its atomic number, which is also equal to the number of electrons in a neutral atom. This number is crucial as it determines the chemical properties and the place of the element on the periodic table.

For example, the atomic number of Hydrogen is 1, which means it has one proton and one electron. The atomic number increases sequentially in the periodic table, and it is this sequential increase that helps to organize elements into a meaningful pattern. Understanding the role of atomic numbers is essential for students, especially when dealing with textbook exercises involving NCERT chemistry solutions.

Element Periods

In the periodic table, 'periods' refer to the horizontal rows. There are seven periods in the periodic table, and each period signifies a new principal energy level being used by the electrons. When the atomic number increases, electrons start populating a new energy level, thus corresponding to a new period.

For example, any element in period 1 has its electrons in the 1s subshell, whereas elements in period 2 have electrons in the 2s and 2p subshells, and so on. This systematic organization helps in predicting the behavior and reactivity of various chemical elements. It is worth noting that the length of each period increases as you move down the table because a larger number of subshells can be occupied by electrons in the higher principal energy levels.

Chemical Elements

Chemical elements are the simplest forms of matter that cannot be broken down using chemical reactions and are made of atoms with the same atomic number. The 118 confirmed elements are organized on the periodic table and they exhibit a diverse array of physical and chemical properties. Elements can be broadly classified into metals, nonmetals, and metalloids based on their characteristics.

Metals tend to be shiny, good conductors of heat and electricity, and malleable, whereas nonmetals often have opposite properties, such as being poor conductors and more brittle. Metalloids have mixed properties of both metals and nonmetals. Chemical elements form the building blocks of all matter and combining them in various ways produces all the compounds and materials that we encounter in our daily life.

NCERT Chemistry

NCERT (National Council of Educational Research and Training) chemistry is an instructional framework that is used extensively in schools across India. It follows a curriculum designed to provide a thorough understanding of chemical principles and practices. Within NCERT chemistry texts, students are introduced to the periodic table, atomic structure, chemical reactions, and much more.

The resources provided by NCERT help in creating a step-by-step learning process for complex concepts, providing a strong foundation in chemistry for students. The structured approach is beneficial in helping students solve textbook exercises, prepare for exams, and even in competitive exams where a solid grasp of fundamental concepts is necessary. Enhancing the clarity of these concepts can be a critical improvement in making the subject more approachable for students.