MPSC PYQ
Science & Technology

Atomic number

Atomic number is a Science & Technology concept from the MPSC syllabus, tested in 5 past MPSC questions across 5 exam years between 2016 and 2025. Below are those real questions with their correct answers and explanations, plus the concepts worth being comfortable with first.

Real questions
5
Years tested
5 · 2016–2025
In context
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Asked in

20252024202220192016

What you need to know first

Periodic table basicsBasic subatomic particlesStructure of atomDefinition of atomic numberProtons and neutronsStructure of an atom

What mastering this unlocks

Isoelectronic speciesSubatomic particles countingElectronic configurationShell structure (K, L, M, N)

Real questions that test this

Carbon compounds are broadly classified into two main categories : 1. Organic compounds : These contain carbon and hydrogen and may also include other elements like oxygen, nitrogen, sulfur etc. They include hydrocarbons (such as methane, ethane, propane), alcohols, acids and polymers (like plastics, rubber). Organic compounds are essential in biological systems, forming the basis of molecules like proteins, carbohydrates, lipids and nucleic acids (DNA and RNA). They are also used widely in industries for example, in the manufacture of fuels, dyes, medicines, pesticides and plastics. 2. Inorganic compounds : These include compounds like Carbon dioxide (CO2), Carbon Monoxide (CO), carbonates (such as calcium carbonate in limestone) and bicarbonates. These compounds are vital in geological and environmental processes, such as the carbon cycle, which maintains the balance of carbon in the eco-system. Carbon compounds exhibit various properties, most organic compounds have low melting and boiling points, are generally flammable and more soluble in organic solvents rather than water. This makes them useful as fuels and industrial solvents. Their diversity and reactivity make them a central part of the field of chemistry, particularly in synthetic and pharmaceutical industries.

कार्बनचा अणुक्रमांक किती आहे ? What is the atomic number of carbon ?

1)04
2)06✓ Correct
3)08
4)12

Carbon is a chemical element with the symbol C and atomic number 6, meaning it has 6 protons in its nucleus.

पुढील दोन विधानांपैकी कोणते अयोग्य आहे ? अ. अणु अंक म्हणजे अणु केंद्रातील एकूण प्रोटॉन्सची संख्या. ब. अणु वस्तुमान म्हणजे अणु केंद्रातील एकूण प्रोटॉन्स व न्यूट्रॉन्सची संख्या. Which one of the following statements is/are incorrect ? a. The number of protons in a nucleus is called its atomic number. b. The total number of protons and neutrons constitute its mass number.

(a)अणु अंक म्हणजे अणु केंद्रातील एकूण प्रोटॉन्सची संख्या. / The number of protons in a nucleus is called its atomic number.

(b)अणु वस्तुमान म्हणजे अणु केंद्रातील एकूण प्रोटॉन्स व न्यूट्रॉन्सची संख्या. / The total number of protons and neutrons constitute its mass number.

1)फक्त अ / Only a
2)फक्त ब / Only b
3)दोनों अ आणि ब / Both a and b
4)दोनों नाहीहत / Neither a nor b✓ Correct

Atomic number is indeed defined as the number of protons in the nucleus, and mass number is the sum of protons and neutrons. Both statements are correct, meaning none is incorrect.

ट्रीटियमचा अणुक्रमांक ______ आहे. An atomic number of Tritium is ______

1)03
2)04
3)02
4)01✓ Correct

Tritium is an isotope of hydrogen. All isotopes of an element share the same atomic number, which is 1 for hydrogen (Protium, Deuterium, and Tritium all have atomic number 1).

खालीलपैकी कोणते वाक्य चुकीचे आहे ? / Which of the following sentence is wrong ?

(a)अणुकेंद्र हे प्रोटॉन व न्यूट्रॉनने बनलेले असते. / Atomic nucleus is made up of protons and neutrons.

(b)प्रोटॉनवर धनभार असतो. / Proton has a positive charge.

(c)इलेक्ट्रॉनवर ऋणभार असतो. / Electron has a negative charge.

(d)न्यूट्रॉनवर धनभार असतो. / Neutron has a positive charge.

1)(III) व (II) / (III) and (II)
2)(II) व (I) / (II) and (I)
3)फक्त (I) / Only (I)
4)फक्त (IV) / Only (IV)✓ Correct

Neutrons are neutral subatomic particles with no electrical charge, so statement (IV) claiming neutrons have a positive charge is factually incorrect.

व्यावहारिक दृष्ट्या अणूचे सारे वस्तुमान मुख्यत्वे त्याच्या पुढील कणांमध्ये एकत्रित असते... / Practically all the mass of an atom is concentrated in its

(a)प्रोटॉन / Protons

(b)न्युट्रॉन / Neutrons

(c)इलेक्ट्रॉन / Electrons

(d)वरील सर्व / All the above

1)फक्त अ / Only a
2)फक्त अ आणि ब / Only a and b✓ Correct
3)फक्त क / Only c
4)फक्त ड / Only d

Practically all the mass of an atom is concentrated in its nucleus, which consists of protons and neutrons (nucleons). Electrons have negligible mass.

More Science & Technology concepts

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