Chemistry Atomic Structure Questions for Railway & SSC CGL Exam 2018: 21st June

Dear Students,

Railway Board offers opulent and revered job posts to its aspirants. And it is not every year that we get the notification from Railway offering a good number of vacant seats to the multitude aspirants. But the current year 2018 brought a pleasant surprise with almost 90,000 seats to be filled by the valid candidates. Opportunity is here but you have to welcome it with a provident strategy. The exam will be conducted in the month of May 2018. 

रेलवे बोर्ड अपने उम्मीदवारों के लिए भव्य और प्रतिष्ठित कार्य पदों की पेशकश करता है. और हर साल ऐसा नहीं होता है कि हमें रेलवे की ओर से अधिसूचना मिलती है. लेकिन वर्तमान वर्ष 2018 आपके लिए बहुत सुखद वर्ष है क्योंकि इसमें लगभग 90,000 सीटों को वैध उम्मीदवारों द्वारा भरा जाएगा. आपके पास बहुत अच्छा अवसर है और आपको इसे एक बेहतर रणनीति से प्राप्त करना होगा. परीक्षा मई 2018 के महीने में आयोजित की जायेगी.

Q1. Constituents of atomic nucleus are- 
परमाणु नाभिक के घटक क्या हैं – 
(a) Electron and proton / इलेक्ट्रॉन और प्रोटॉन
(b) Electron and neutron/ इलेक्ट्रॉन और न्यूट्रॉन
(c) Proton and neutron / प्रोटॉन और न्यूट्रॉन
(d) Proton, neutron and electron / प्रोटॉन, न्यूट्रॉन और इलेक्ट्रॉन

Show Answer
Sol. The constituents of an atom are protons, neutrons and electrons. The protons and neutrons (nucleons) are found in the nucleus of atoms. The nucleus of an atom is surrounded by electrons. 

Q2. Which of the following is not a part of an atom? 
निम्नलिखित में से कौन एक परमाणु का हिस्सा नहीं है?
(a) Electron /इलेक्ट्रॉन
(b) Proton /प्रोटॉन
(c) Neutron / न्यूट्रॉन
(d) Photon / फोटॉन

Show Answer
Sol. Proton, electron and neutron are part of an atom. These particles are also known as three fundamental particles, but the photon is associated with light energy and also known as energy packet of light.

Q3. The atomic nucleus was discovered by: 
परमाणु नाभिक _________ द्वारा खोजा गया था: 
(a) Rutherford /रदरफोर्ड
(b) Dalton / डाल्टन
(c) Einstein / आइंस्टाइन
(d) Thompson / थॉम्पसन

Show Answer
Sol. The nucleus is a very dense region consisting of protons and neutrons at the centre of an atom. It was discovered in 1911 as a result of Ernest Rutherford’s interpretation of the 1909 Geiger-Marsden gold foil experiment. The proton neutron model of the nucleus was proposed by Dmitri Ivanenko 1932.

Q4. In atom, neutron was discovered by: 
परमाणु में, न्यूट्रॉन की खोज किसके द्वारा की गई थी?
(a) J.J. Thomson / जे.जे. थॉमसन
(b) Chadwick / चाडविक
(c) Rutherford / रदरफोर्ड
(d) Newton / न्यूटन

Show Answer
Sol. Neutron is a neutral particle which has no electrical charge. It was discovered by Chadwick in 1932. He discovered that when Beryllium (Be) or other atoms are bombarded with high speed particles, then electrically neutral particles emerges from these atoms and such neutral particles are known as neutrons.

Q5. Which of the following is not a subatomic particle? 
निम्नलिखित में से क्या एक उप – परमाणविक कण नहीं है?
(a) Neutron/ न्यूट्रॉन
(b) Proton / प्रोटॉन
(c) Deuteron / ड्यूटरान
(d) Electron / इलेक्ट्रॉन

Show Answer
Sol. The particles that are smaller than the atoms are called subatomic particles. The three main subatomic particles that form an atom are protons, neutrons and electrons. Deuteron contains a proton and a neutron.

Q6. The Nucleus of Helium has- 
हीलियम के न्यूक्लियस में-
(a) Only one neutron / केवल एक न्यूट्रॉन
(b) Two protons   / दो प्रोटॉन
(c) Two protons and two neutrons / दो प्रोटॉन और दो न्यूट्रॉन
(d) One proton and two neutrons / एक प्रोटॉन और दो न्यूट्रॉन

Show Answer
Sol. Helium- (2He4) is a non-radioactive isotope of the element Helium. It is by far the most abundant of the two naturally occurring isotopes of Helium, making up about 99.99986% of the Helium on earth. Its nucleus is identical to an alpha particle and consists of two protons and two neutrons. 

Q7. Which of the following carries a negative charge? 
निम्नलिखित में से किसमें ऋणात्मक आवेश है?
(a) X-rays / एक्स-रे
(b) Alpha particles / अल्फा कणों
(c) Beta particles / बीटा कणों
(d) Gamma rays / गामा किरणें

Show Answer
Sol. Alpha rays or Alpha particles (α) are the positively charged particles. Beta particles (β) are highly energetic electrons which are released from inner part (β) of a nucleus. They are negatively charged (–1) and have a negligible mass. Gamma radiation (γ) consist of photons, which travel at the speed of light like all electromagnetic radiations. A ray has no mass or charge. Gamma radiation can travel much faster (speed of light) in the air than Alpha and Beta. 

Q8. What is the mass number of an element, the atom of which contains two protons, two neutrons and two electrons? 
एक तत्व की द्रव्यमान संख्या क्या है, जिसमें परमाणु दो प्रोटॉन, दो न्यूट्रॉन और दो इलेक्ट्रॉनों को शामिल करता है?
(a) 2
(b) 4
(c) 6
(d) 8

Show Answer
Sol. The mass number of an element is the sum of a total number of protons and neutrons inside in its nucleus and represents by A. Therefore, mass number A= number of proton+number of neutron. Therefore, mass number = 2 + 2 = 4 

Q9. The atoms, in which the number of protons is same but the number of neutrons is different, are known as- 
परमाणु, जिसमें प्रोटॉन की संख्या एक समान है लेकिन न्यूट्रॉन की संख्या अलग है, इसे किस रूप में जाना जाता है- 
(a) Isobars / आइसोबार्स
(b) Isomers / आइसोमर्स
(c) Isotones / आइसोटोन्स
(d) Isotopes/ आइसोटोप

Show Answer
Sol. The Isotopes are a set of nuclides/atoms having the same number of protons, but a different number of neutrons. In other words, the same atomic number having different atomic mass. Each individual isotope has a separate nuclei. The Isotopes that are unstable and undergo radioactive decay are called Radioisotopes.

Q10. The isoneutronic group, in the following, is: 
निम्नलिखित में आइसोन्यूट्रोनिक ग्रुप, है:

Show Answer
Sol. Two nuclides are isoneutronic (isotones) if they have the very same neutron number N, but different proton number Z. For example, Boron-12 and Carbon-13 nuclei both contain 7 neutrons, and so are Isotones.

Q11. Radioactivity is measured by- 
रेडियोधर्मिता को किसके द्वारा मापा जाता है-
(a) Hydrometer / हाइड्रोमीटर
(b) Geiger Counter / गीगर काउंटर
(c) Seismometer / भूकम्पमान
(d) Ammeter/ एम्मिटर

Show Answer
Sol. The Geiger-Muller Counter also called a Geiger Counter, is an instrument used for detection and measurement ionizing radiation. It detects radiation such as Alpha particles, Beta particles and Gamma rays using the ionization produced in a Geiger-Muller tube, which given its name to the instrument.

Q12. Radioactivity was discovered by: 
रेडियोधर्मिता की खोज किसके द्वारा कि गई थी?
(a) Rutherford / रदरफोर्ड
(b) Becquerel / बेक्कुएरेल
(c) Bohr / बोह्र
(d) Madam Curie / मैडम क्यूरी

Show Answer
Sol. Radioactivity was discovered in 1896 by the French Scientist Henri Becquerel when he was working with phosphorescent materials.

Q13. Change of water into the vapour is called- 
पानी के वाष्प में परिवर्तन को कहा जाता है-
(a) Natural / प्रकृतिक
(b) Physical / शारीरिक
(c) Chemical / केमिकल
(d) Biological / जैविक
Show Answer
Sol. Change of water into the vapour is called a physical change.

Q14. Pasteurization is a process by which- 
पाश्चरराइजेशन एक प्रक्रिया है जिसके द्वारा- 
(a) Milk is preserved at a very low temperature for 24 hours / दूध 24 घंटों के लिए बहुत कम तापमान पर संरक्षित होता है.
(b) Milk is heated for 8 hours / दूध 8 घंटे तक गरम किया जाता है.
(c) First milk is heated to a certain temperature and then cooled suddenly within specified time / पहले दूध को निश्चित तापमान तक गरम किया जाता है और फिर निश्चित समय के भीतर अचानक ठंडा हो जाता है
(d) None of these / इनमें से कोई नहीं

Show Answer
Sol. In order to pasteurize milk, first, the milk is heated up to a longer time and then cooled suddenly within specified time. Pasteurization is a process invented the by French Scientist Louis Pasteur during the nineteenth century. In 1864, Louis Pasteur discovered that heating beer and wine was enough to kill most of the bacteria that caused spoilage and hence, prevented these beverages from turning sour. This was achieved by eliminating pathogenic microbes and lowering microbial numbers to prolong the quality of the beverage.

Q15. Because of impurities the boiling point of water generally- 
सामान्यतः अशुद्धियों के कारण पानी का गलनांक बिंदु – 
(a) Increases / बढ़ता है
(b) Decreases / घटता है
(c) Remains constant / स्थिर रहता है
(d) They are not related / वे संबंधित नहीं हैं

Show Answer

Sol. The boiling point of a liquid is the temperature at which its vapour pressure is equal to the pressure of the gas above it. The normal boiling point of a liquid is the temperature at which its vapour pressure is equal to one atmosphere (760 tor).

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