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This is the second of our many quizzes on Atomic structure. Click on this to access more such competitive quizzes on General Chemistry.

Atomic structure Quiz 2

chemistry

 In the structure of ${{d}_{{{z}^{2}}}}$ orbital given below, the donut (central ring) represents:<img  src="https://cmds-vedantu.s3.ap-southeast-1.amazonaws.com/prod/question-sets/bb95337e-9745-4eeb-b4aa-b645b635f50c3515838061609812960.png"/>

 Orbitals are always filled with the negative ions and the central ring of the ${{d}_{{{z}^{2}}}}$ orbital is concentrated with the same negative ions.

The orbital has a single dumbbell along the Z-axis and collar-like region on the XY plane. It has the toroidal shape that is a donut shaped ring wherein the electrons with the energy of d-orbital is most likely to be found.

 Identify the set of isotones among the following.

 Isotones are found for the atoms of different elements with the same neutrons and different mass numbers and are also of different proton numbers.

 Isotones are those which contain the same number of neutrons in atoms of the different elements. In the options given, option A has the isotones set where for the carbon atom A - Z = 14 - 6 = 8 and for nitrogen 15-7=8 and for oxygen 16-8=8. Thus, all have the same neutrons with different atoms and different mass numbers.

 What will be the wavelength associated with an electron moving with a kinetic energy of $5.0\times {{10}^{-25}}J$ ? mass of electron = $9.1\times {{10}^{-31}}$ kg

 The equation used for finding the wavelength associated with the moving electron is given by the De-Broglie wavelength that is $\lambda =\dfrac{h}{mv}$

 We know that kinetic energy is given by the formula, $\\ K.E.=\dfrac{1}{2}m{{v}^{2}}.$ We know that the mass of an electron is  $9.1\times {{10}^{-31}}kg. \\$ By using the given data, substitute the values, we get $5.0\times {{10}^{-25}}=\dfrac{1}{2}\times 9.1\times {{10}^{-31}}\times {{v}^{2}} \\ \text{Thus, velocity }v=\sqrt{\dfrac{2\times 5.0\times {{10}^{-25}}}{9.1\times {{10}^{-31}}}} \\ =1.048\times {{10}^{3}}m{{s}^{-1}} \\ \text{Now, wavelength of moving electron is given by,} \\  \lambda =\dfrac{h}{mv}=\dfrac{6.62\times {{10}^{-34}}Js}{9.1\times {{10}^{-31}}kg\times 1.048\times {{10}^{3}}m{{s}^{-1}}} \\ =0.694\times {{10}^{-6}}m \\$. This can also be written as, 694 nm.

 What will be the value of $l$ for the orbital which has a complex shape?

The orbital having the complex shapes is the f-orbital which makes it take the values of $l$ as the next number of the d-orbital.

 The shape of the three orbitals that is s, p and d have the spherical, and dumbbell along with one orbital along with donut in its Z-axis respectively. The f orbitals on the other hand are having the complex shape and is said to be having the tetrahedral shape. This makes the Azimuthal quantum number as l=3.

 In the emission spectrum of hydrogen shown below, hydrogen gas at very low pressure undergoes dissociation into atoms because of: <img  src="https://cmds-vedantu.s3.ap-southeast-1.amazonaws.com/prod/question-sets/dd512962-8312-405a-8e90-dea46f7d836a8289690676850054179.png"/>  

 The energy required for the dissociation of hydrogen into atoms will require higher energy and thus the Balmer series is obtained in this emission spectrum of hydrogen.

 When a hydrogen gas at very low pressure is taken in a discharge tube and is subjected to a high potential difference, the hydrogen molecules absorb energy and undergo dissociation into atoms. These atoms get excited to a higher energy level and emit the light when it returns to the original level.