Class 11 Chemistry -Ch#2 Atomic Structure Numerical Questions

Summary

In this video, Mohammad Talha from Talash Academy explains how to solve two key numerical problems in chemistry related to atomic structures. The first problem focuses on calculating the radius of hydrogen's third orbit using a simple formula, and the second problem involves using wave numbers to determine electron transitions between energy levels. Talha walks through both problems step by step, illustrating the process of using known constants and formulas for precise calculations. The tutorial is geared toward making atomic structure problems more accessible for students by simplifying complex concepts.

Takeaways

• 😀 The script focuses on solving numerical problems from Chapter 2 on Atomic Structures in Chemistry.
• 😀 The first numerical question involves calculating the radius of hydrogen in its third orbit using a simple formula.
• 😀 The constant used for calculating hydrogen's radius is 0.529 angstroms, which is equal to 10^(-10) meters.
• 😀 The formula for calculating the radius of any hydrogen orbit is: Rn = n^2 * R1, where n is the orbit number and R1 is the radius of the first orbit.
• 😀 In the third orbit, the radius is calculated by plugging n=3 into the formula, giving the result of 4.761 angstroms.
• 😀 The second question involves a transition of an electron from a higher energy orbit to n=2, and the task is to determine the spectral line.
• 😀 The wave number for the transition is given as 2310 x 10^5 meters inverse, and the formula for the wave number is related to the orbital transition.
• 😀 The formula for the wave number is: Wave number = R * (1/n1^2 - 1/n2^2), where R is the Rydberg constant, and n1 and n2 are the initial and final orbit numbers.
• 😀 In this case, the lower orbit (n1) is 2, and the goal is to find the higher orbit (n2).
• 😀 After simplifying the equation, n2 is found to be approximately 5, indicating the electron jumped from the 5th orbit to the 2nd orbit, corresponding to the Balmer series.
• 😀 The script concludes by suggesting that remembering the different series (like the Balmer series) can help identify transitions based on the orbits involved.

Q & A

What is the formula for calculating the radius of the hydrogen atom in the third orbit?

The formula for calculating the radius of hydrogen in the third orbit is: r3 = n^2 * r1, where n is the orbit number and r1 is the radius of the first orbit (0.529 Å). For the third orbit (n = 3), r3 = 9 * 0.529 Å = 4.761 Å.

What is the value of the radius of the first orbit of hydrogen?

The radius of the first orbit (r1) of hydrogen is 0.529 Å (angstrom).

What is the significance of the constant 0.529 angstrom in this context?

The constant 0.529 angstrom represents the radius of the first orbit of the hydrogen atom and is used to calculate the radii of other orbits in the hydrogen atom.

How can you calculate the radius for any orbit of hydrogen?

The radius for any orbit of hydrogen can be calculated using the formula: r = n^2 * r1, where n is the orbit number and r1 is the known radius of the first orbit (0.529 Å).

What is the given wave number in the second question and what unit is it measured in?

The given wave number in the second question is 2310 × 10^5 m^-1, and it is measured in meters inverse (m^-1).

What does the wave number indicate in the context of atomic transitions?

The wave number is related to the energy of the photon emitted or absorbed during an electron transition between energy levels of an atom. Higher wave numbers correspond to higher energies.

What is the significance of the constant 1.096 × 10^7 m^-1 in the second question?

The constant 1.096 × 10^7 m^-1 is the Rydberg constant, which is used in the formula for calculating the wave number of spectral lines during transitions between energy levels in hydrogen.

What formula is used to find the wave number during electron transitions?

The formula used is: wave number (1/λ) = Rydberg constant (1.097 × 10^7 m^-1) * (1/n1^2 - 1/n2^2), where n1 is the lower orbit and n2 is the higher orbit.

How do you determine the series of spectral lines based on the transition?

The series of spectral lines is determined by the final orbit that the electron transitions to. If the electron ends in the second orbit (n = 2), the spectral lines belong to the Balmer series.

In the second question, what orbit is the electron jumping from and what is the corresponding spectral series?

The electron is jumping from the fifth orbit (n = 5) to the second orbit (n = 2). This transition corresponds to the Balmer series of spectral lines.