Structure of The Atom (परमाणु की संरचना) Ch(4) Practice Quiz in Hindi Part – 1 || Class 9 Science Practice Quizzes in English

explanation: Using the formula 2n^2, where n = 3 for the third shell M-shell), the maximum capacity is 2 3^2 = 18.

explanation: The maximum number of electrons that can be accommodated in a shell is given by the formula 2n^2, where n is the shell number. For the second shell L-shell), n = 2, so the maximum capacity is 2 2^2 = 8.

explanation: Magnesium has 2 electrons in its outermost shell, which it can lose to achieve a stable octet. Therefore, its valency is 2.

explanation: Rutherford’s experiment showed that most alpha particles passed straight through the gold foil, indicating that atoms are largely empty space.

explanation: The valency of an element is determined by the number of electrons it needs to gain or lose to achieve a stable octet 8 electrons) in its outermost shell. An element with 7 electrons in its outermost shell needs to gain 1 electron, so its valency is 1.

explanation: Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons, resulting in different mass numbers.  

explanation: Protium, deuterium, and tritium are the three isotopes of hydrogen. They all have 1 proton but differ in the number of neutrons.

explanation: Neutrons are neutral subatomic particles found in the nucleus of all atoms, except for the most common isotope of hydrogen, which has only a proton in its nucleus.

explanation: Electrons, particularly those in the outermost shell valence electrons), are involved in chemical bonding and determine the reactivity and chemical behavior of an element.

explanation: Isotopes of an element have the same number of protons and electrons, which determine their chemical behavior. However, they differ in the number of neutrons, leading to slightly different physical properties.

explanation: The atomic number is a fundamental property of an element and is equal to the number of protons in the nucleus of its atoms.

explanation: The outermost shell of an atom can accommodate a maximum of 8 electrons, according to the octet rule.

explanation: Oxygen has 6 electrons in its outermost shell and needs to gain 2 electrons to achieve an octet. Therefore, its valency is 2.

explanation: J.J. Thomson’s experiments with cathode rays led to the discovery of the electron.

explanation: Isobars are atoms of different elements that have the same mass number. Calcium-40 and Argon-40 both have a mass number of 40 but different atomic numbers.

explanation: Chlorine has 17 electrons. Following the rules of electron distribution, the first shell K-shell) can hold a maximum of 2 electrons, and the second shell L-shell) can hold a maximum of 8 electrons. The remaining 7 electrons occupy the outermost shell M-shell).

explanation: The mass number represents the total number of nucleons protons and neutrons) in the nucleus of an atom.

explanation: Thomson’s model proposed that electrons were embedded in a positively charged sphere, similar to how plums are distributed in a Christmas pudding.

explanation: Protons are positively charged subatomic particles.

explanation: Isotopes are atoms of the same element with different mass numbers. 12C and 14C are both isotopes of carbon, with 6 and 8 neutrons respectively.