Electronic Configuration and Types of Elements MCQ Quiz - Objective Question with Answer for Electronic Configuration and Types of Elements - Download Free PDF

Key Points

• Potassium (K) is more reactive than sodium (Na), calcium (Ca), and iron (Fe). Hence, option 2 is correct.
• Reactivity increases down the group in the alkali metals (Group 1 of the Periodic Table).
• Order of reactivity: Potassium > Sodium > Calcium > Iron
• Potassium reacts violently with water, producing potassium hydroxide and hydrogen gas, often with flame or explosion.

The correct answer is Oxygen.

Key Points

• Oxygen is a chemical element with the atomic number 8.
• It is represented by the symbol O in the periodic table of elements.
• Oxygen is a highly reactive non-metal and an oxidizing agent that readily forms oxides with most elements and compounds.
• It is essential for most life forms on Earth, as it is a critical component of cellular respiration.
• Oxygen constitutes about 21% of the Earth's atmosphere by volume.
• It is also a part of water (H₂O) and is necessary for combustion processes.
• Oxygen was discovered independently by Carl Wilhelm Scheele and Joseph Priestley in the 1770s.

 Additional Information

•  Hydrogen
  • Hydrogen is the lightest and most abundant element in the universe, with the atomic number 1.
  • It is represented by the symbol H.
  • Hydrogen is primarily found in water (H₂O) and is essential for the formation of many compounds.
• Nitrogen
  • Nitrogen is a chemical element with the atomic number 7.
  • It is represented by the symbol N.
  • Nitrogen makes up about 78% of the Earth's atmosphere and is a crucial component of the biosphere and ecosystems.
• Carbon
  • Carbon is a chemical element with the atomic number 6.
  • It is represented by the symbol C.
  • Carbon is the basis of all known life on Earth, forming the backbone of organic chemistry.

The correct answer is option 2.

Key Points

• Noble gases have a complete valence shell, making their electronic configuration stable.
• The typical electronic configuration of noble gases is 2, 8, 18, 18, 8.
• Option 2 (2, 8, 18, 2) does not represent a noble gas configuration, as it does not end with a full valence shell.
• Option 1 (2, 8, 18, 8) and Option 4 (2, 8, 18, 18, 8) are valid noble gas configurations.
• Option 3 (2, 8) represents the noble gas neon.

Additional Information

• Noble Gases
  • Noble gases are elements in Group 18 of the periodic table.
  • They are known for their lack of reactivity due to their full valence electron shell.
• Valence Electrons
  • Valence electrons are the outermost electrons of an atom and determine its ability to bond with other atoms.
  • Atoms with a full valence shell are generally inert and stable.
• Periodic Table Trends
  • Elements are arranged in the periodic table in order of increasing atomic number.
  • The configuration of electrons follows a specific order and affects the chemical properties of the elements.

The correct answer is 6.

Key Points

• The Elements of group 16 such as Oxygen, Sulfur, Selenium, Tellurium, Polonium and all have 6 electrons on the outermost cell.
• The 's' valence shells always contain 2 electrons, the 'p' valence shell contains 4 electrons.

• The elements present in group 16 consist of oxygen (0), sulfur (S), selenium (Se), tellurium (Te), and polonium (Po).

• Of all the elements, only Polonium is radioactive. 
• Group 16 electron configuration indicates that its members of Group 16 have six elements in its valence shell, and therefore require two elements to complete the octet valency.
• Therefore, all the elements of group 16 are negatively charged since they can receive two electrons from other elements. 

Important Points

The correct answer is O.

Key Points

• Atomic radius - 
  • The shortest distance between the atom's nuclei and the outermost shell of the atom is called the 'Atomic Radius'.
  • The exact value of the atomic radius of an atom cannot be known.
  • Because the atom is not found in a free state nor can the exact position of the electron be known.​
  • In general, the atomic radius decreases across a period and increases down a group.

Additional Information

• Please note that these atomic radii values are approximate and may vary depending on the source and method of measurement. They are expressed in picometers (pm), where 1 pm = 1 x 10^-12 meters.

The correct answer is Zn.

Key Points

• Only a few elements have been found to be absolutely essential for plant growth and metabolism.
• These elements are further divided into two broad categories based on their quantitative requirements: (i) Macronutrients, and (ii) Micronutrients.
• Macronutrients are generally present in plant tissues in large amounts.
  • The macronutrients include carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorous (P), sulphur (S), potassium (K), calcium (Ca) and magnesium (Mg).
  • Of these, carbon, hydrogen and oxygen are mainly obtained from CO₂ and H₂O, while the others are absorbed from the soil as mineral nutrition.
• Micronutrients or trace elements are needed in very small amounts.
  • These include iron, manganese (Mn), copper (Cu), molybdenum (Mo), zinc (Zn), boron (B), chlorine (Cl) and nickel (Ni).

Additional Information

• In addition to the 17 essential elements named above, there are some beneficial elements such as sodium (Na), silicon (Si), cobalt (Co) and selenium (Se). They are required by higher plants

The correct answer is 5,6,7 or 8.

CONCEPT:

• The outermost shell of an electron can accommodate a maximum of 8 electrons.
• Elements having filled outermost shell are stable. So all elements tend to attain a stable state by completing its octet.
• Elements attain this stable form by losing or gaining electrons.

EXPLANATION:

• The effective nuclear charge experienced by the outer shell electrons in non-metals is very high.
• So they can accept electrons instead of losing electrons. 
• Electonic configurations of some non-metals:

 Additional Information

Chemical properties of non - metals

1. Electronic configuration: Most of the non - metals have 4 to 7 electrons in their valence shells.
2. Formation of ions: Non - metals tend to accept electrons in their valence shell to form negatively charged ions called anions.
3. Reaction with oxygen: Non - metals combine with oxygen to form their oxides.

The correct answer is 6.

Key Points

• The Elements of group 16 such as Oxygen, Sulfur, Selenium, Tellurium, Polonium and all have 6 electrons on the outermost cell.
• The 's' valence shells always contain 2 electrons, the 'p' valence shell contains 4 electrons.

• The elements present in group 16 consist of oxygen (0), sulfur (S), selenium (Se), tellurium (Te), and polonium (Po).

• Of all the elements, only Polonium is radioactive. 
• Group 16 electron configuration indicates that its members of Group 16 have six elements in its valence shell, and therefore require two elements to complete the octet valency.
• Therefore, all the elements of group 16 are negatively charged since they can receive two electrons from other elements. 

Important Points

The correct answer is Silicon.

Key Points

• The elements that show properties that are intermediate between metals and non-metals are called metalloids.
• Metalloid lies at the borderline between metals and non-metals 
• Metalloids have nonmetallic chemical properties in general.
• Metalloids are usually too brittle to have any structural uses
• Examples of metalloids are.
  • Boron.
  • Silicon.
  • Germanium.
  • Arsenic.
  • Antimony.
  • Tellurium.
  • Polonium.

Important Points

• Silicon is a chemical element atomic number 14.
  • Silicon is mainly used in computer chips as it is a semiconductor.
  • Silicon in silicones can be used as a waterproof sealant on roofs, around water pipes.
  • It was discovered by Jons Jacob Berzelius in 1823.
  • Silicon was named by Thomas Thomson in 1817.

Additional Information

• Bromine is a chemical element atomic number 35.
  • Bromine is a nonmetal in group 17.
• Lead is a chemical element atomic number 82.
  • Lead is a metal in Group 14
• Gold is a chemical element atomic number 79.
  • Gold is a transition metal and a group 11 element.

The correct answer is Nitrogen.

• Bulbs are filled with chemically inactive gases like Nitrogen or Argon to prevent the oxidation of tungsten filament used in the bulb.

Mistake PointsAny Inert gases or noble gases can be filled in electric bulbs Here, Nitrogen is one of them. 

Key Points

About Nitrogen:

• It is the chemical element with atomic number 7 and denoted by Symbol by (N). 
• Nitrogen gas constitutes 78% of Earth's Air.
• Nitrogen is odourless, Colorless, and generally considered as an Inert Gas in Nature.
• Nitrogen was discovered by chemist and physician Daniel Rutherford in 1772.

Nitrogen:

Additional Information

• Hydrogen
  • The atomic number is 1 and denoted by the symbol (H).
  • It was discovered by Henry Cavendish.
• Carbon dioxide
  • The atomic number is 6 and denoted by the symbol (CO2). 
  • It was discovered by Joseph Black.
• Oxygen
  • The atomic number is 8 and denoted by the symbol (O).
  • It was discovered by Antoine Lavoisier, Joseph Priestley, and Carl Wilhelm Scheele.

The Correct Answer is Silver.

Key Points

• Lead (Pb):
  • The atomic number is 82.
  • It is a soft, highly malleable, ductile, and a relatively poor conductor of electricity.
  • It is very much corrosion resistant.

Additional Information

• Silver (Ag):
  • The atomic number is 47.
  • It is a soft, white, and lustrous metal.
  • It is a very ductile and malleable metal and has the highest electrical conductivity, thermal conductivity of all elements i.e best conductor of heat.
  • It is most widely used for electrical cables and wirings.
• Mercury (Hg):
  • The atomic number is 80.
  • It is the only metal liquid at standard temperature and pressure.
  • It is also known as Quicksilver.
  • Mercury has a relatively high vapour pressure and the highest volatility of any metal.
  • It is used in making batteries, thermometers, and barometers, etc.
  • It is a good conductor of heat.
• Stainless steel:
  • It is an alloy of Iron and Chromium with a minimum of 10% among other alloying elements.
  • It is resistant to corrosion.
  • Stainless steels have a much lower conductivity than that of carbon (mild) steel.

Confusion Point

•  Silver(Ag) is the best conductor of heat and electricity.

The correct answer is n².

• The maximum number of electrons that can be present in a shell is given by the formula 2n ².

$\Rightarrow \frac{2n^2}{2}=n^2$

• Half of the maximum is n 2.
• ‘n’ is the orbit number or energy level index, i.e. 1, 2, 3,….
• According to the given formula −
• First orbit i.e. K-shell will be = 2 × 1² = 2
• Second orbit i.e. L-shell will be = 2 × 2² = 8
• Third orbit i.e. M-shell will be = 2 × 3² = 18
• Fourth orbit i.e. N-shell will be = 2 × 4² = 32

Notes:

• Electronic configuration filled according to the Aufbau principle.
• Aufbau Principle:
  • It states that electrons are filled into atomic orbitals in the increasing order of orbital energy levels.
  • The order of energy level is 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, and so on.

Mistake Points

The question asked for half the total maximum- 

∴ instead of 2n² we go with, n² 

The correct answer is Stays the same. 

Key Points

• In a group, the electrons in the outermost orbit are the same. 
• There is a total of 18 groups in the Periodic table.
• There is a total of 4 blocks in the Periodic table. 
• Group 18 consists of the Noble gases because the outermost orbit has completely filled.
• Each atom consists of electrons and nuclei.

Additional Information

• The Father of the Modern Periodic table is Dimitri Ivanovich Mendeleev.(published in 1869 with 63 elements)
• The element with the lowest melting and boiling point is Helium.
• The element with the highest melting point is Carbon.
• The element with the highest boiling point is Tungston.
• The element with the highest density is Osmium.
• The element with the highest electronegativity is Fluorine. 

Valency is the combining power of an element. Elements in the same group of the periodic table have the same valency.

Key Points

• Valency is the no of electron that looses, shared or gain to achieve stability or we can say to complete it outer most shell.
• If any element has valence electron (electrons present in outer most shell) less than 4
  • ​​Valency = no of valance electron (valence electron<4)
• If any element has valence electron ​more than 4
  • ​​Valency = 8 - no of valance electron (valence electron>4)

​For Lithium:

• Li(Z=3) Electronic configuration = 2, 1
  • Valency = no of valance electron  = 1

​Hence, we can conclude that 1 is the valency of Lithium.

The Correct Answer is A mixture of Iron filings and sand.

• Homogenous mixture:
  • A mixture is said to be homogenous if it has a uniform composition throughout and there are no visible boundaries of separation between constituents.
  • Moreover, the constituents can not be seen even by a microscope.
  • Examples: Common salt dissolved in water, Sugar dissolved in water, Methyl alcohol in water, Iodine dissolved in CCl4 and Benzene in Toulene.
• Heterogenous mixture:
  • A mixture is said to be heterogeneous if it does not have a uniform composition throughout and has visible boundaries of separation between various constituents.
  • The different constituents of the heterogeneous mixture can be seen even with the naked eye.
  • Examples: A mixture of Sulphur and Sand, A mixture of Iron Filings and Sand etc.