Classification of Elements and Periodicity in Properties MCQ Quiz - Objective Question with Answer for Classification of Elements and Periodicity in Properties - Download Free PDF

CONCEPT:

Electronic Configuration of Transition Metals

• Transition metals are elements found in the d-block of the periodic table.
• These elements have partially filled d orbitals and typically show a variety of oxidation states.
• The electronic configuration of transition metals includes filling the 3d orbitals after the 4s orbitals.

EXPLANATION:

• Option A: [Ne]3s²3p⁶4s²3d⁶ is the electronic configuration of Iron (Fe), a transition metal, located in the d-block of the periodic table.
• Option B: [Ar]3d⁸4s² is the electronic configuration of Nickel (Ni), a transition metal, also found in the d-block.
• Option C: [Kr]4s²4d⁷5p³ is not a transition metal configuration. It corresponds to an element in the p-block (Arsenic, As), not a transition metal.
• Option D: [Xe]4f¹⁴5d⁷6s² is the electronic configuration of a lanthanide element (e.g., Dysprosium), not a transition metal, as it involves filling the 4f orbitals.

Therefore, the correct answer is: A and B only.

CONCEPT:

Trends in Ionic Sizes

• Ionic size is influenced by the number of protons, electrons, and electron-electron repulsion in an ion.
• In general:
  • Cations are smaller than their parent atoms due to the loss of electrons, resulting in reduced electron-electron repulsion and stronger attraction of the remaining electrons to the nucleus.
  • Anions are larger than their parent atoms due to the gain of electrons, increasing electron-electron repulsion and slightly weakening the attraction of the electrons to the nucleus.
• For isoelectronic species (ions with the same number of electrons), the ionic size decreases as the nuclear charge increases. This is because a higher nuclear charge pulls the electrons closer to the nucleus.

EXPLANATION:

• The ions F^-, Na⁺, O^2-, Al³⁺, and Mg²⁺ are isoelectronic (all have 10 electrons).
• The nuclear charges of these ions are as follows:
  • Al³⁺: +13
  • Mg²⁺: +12
  • Na⁺: +11
  • F^-: +9
  • O^2-: +8
• Higher nuclear charge results in stronger attraction of electrons to the nucleus, leading to smaller ionic size.
• Therefore, the correct order of increasing ionic size is:

  Al³⁺ < Mg²⁺ < Na⁺ < F^- < O^2-

Therefore, the correct answer is Al³⁺ < Mg²⁺ < Na⁺ < F^- < O^2-.

CONCEPT:

The International Union of Pure and Applied Chemistry (IUPAC) systematically assigns temporary names to newly discovered or synthesized elements based on their atomic numbers until permanent names are given. These temporary names follow specific guidelines.

• The naming convention uses Latin roots for the digits of the atomic number.
• The suffix "-ium" is added at the end for elements.
• Each digit of the atomic number is represented by a corresponding Latin root:
  • 1 = "un"
  • 2 = "bi"
  • 3 = "tri"
  • ... and so on.
• For example, for atomic number 112:
  • 1 = "un"
  • 1 = "un"
  • 2 = "bi"
• The temporary IUPAC name becomes "Ununbium."

EXPLANATION:

• The element with atomic number 112 was assigned the temporary name "Ununbium" following the IUPAC naming rules.
• In the given options:
  • "Unnilennium" is incorrect because it does not follow the correct naming convention for atomic number 112.
  • "Ununnilium" is incorrect; it corresponds to atomic number 110.
  • "Unununium" is incorrect; it corresponds to atomic number 111.
  • "Ununbium" is correct, as it follows the Latin roots for atomic number 112.

Therefore, the IUPAC name of the element with atomic number 112 is "Ununbium,".

CONCEPT:

Periodic Table and Blocks

• The modern periodic table is divided into four blocks: s-block, p-block, d-block, and f-block.
• The classification into blocks is based on the type of orbital (s, p, d, or f) in which the last electron enters.
• The s-block elements have their outermost electron in an s orbital, p-block in a p orbital, d-block in a d orbital, and f-block in an f orbital.

EXPLANATION:

• The atomic number 37 corresponds to the element Rubidium (Rb).
• The electronic configuration of Rubidium is:
  1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s¹
• The last electron enters the 5s orbital, which is part of the s-block.
• The s-block is located on the left side of the periodic table and includes groups 1 (alkali metals) and 2 (alkaline earth metals).

Therefore, the element with atomic number 37 (Rubidium) belongs to the s-block in the modern periodic table.

CONCEPT:

Oxides of Carbon

• CO (Carbon Monoxide): CO is a neutral oxide. It does not exhibit acidic or basic properties, and it is sparingly soluble in water.
• CO₂ (Carbon Dioxide): CO₂ is an acidic oxide. It reacts with water to form carbonic acid (H₂CO₃), which is a weak acid. Thus, CO₂ is acidic in nature.
• An oxide that reacts with water to form an acid is considered an acidic oxide. Hence, CO₂ forms carbonic acid, which makes it acidic in nature, whereas CO does not react with water to form an acid.

EXPLANATION:

• Assertion A: This is correct. Carbon forms two important oxides: CO, which is neutral, and CO₂, which is acidic in nature.
• Reason R: This is also correct. CO₂ can combine with water to form carbonic acid (H₂CO₃), while CO is sparingly soluble in water and does not form an acid.
• However, Reason R does directly explain why CO is neutral and CO₂ is acidic in nature. The acidity of CO₂ is due to its ability to form carbonic acid, but the neutral nature of CO is due to its lack of acidity or basicity when dissolved in water.

Therefore, the correct answer is Both A and R are correct but R is the correct explanation of A.

The correct answer is 1.

The correct answer is Alkali metals 

Key Points

• Alkali metals:-
  • Alkali metals have the largest atomic size in their respective periods.
  • This translates to a weaker attraction between the positively charged nucleus and the outermost (valence) electron.
  • As a result, less energy is needed to remove this electron, leading to a lower ionization potential.

Additional Information

• Alkaline earth metals:-
  • These come after alkali metals in a period and while they are relatively large, they have two valence electrons compared to just one for alkali metals. 
  • This increases the effective nuclear charge experienced by the valence electrons, slightly raising their ionization potential compared to alkali metals.
• In contrast, halogens are on the rightmost side of the period and have one electron less than a full valence shell. They attract their valence electrons strongly, resulting in high ionization potentials.
• Inert gases have filled valence shells, achieving a stable configuration. Removing an electron from such a stable configuration requires a lot of energy, resulting in very high ionization potentials.

The correct answer is Potassium-Po.

Key Points

• Potassium:
  • ​Potassium is a chemical element with the symbol K.
  • The Atomic number of potassium is 19.
  • It is a silvery-white metal that is smooth enough to be sliced with little force with a knife.
  • Potassium reacts rapidly with atmospheric oxygen within seconds of exposure to form flaky, white potassium peroxide.

Additional Information

Phosphorus	Phosphorus is a chemical element with atomic number 15. The symbol of phosphorus is P. It was discovered by Hennig Brand in 1669.
Iron	Symbol Fe and atomic number = 26. Wrought Iron is the purest form of iron. The Most impure form of Iron is Pig Iron.
Iodine	Iodine is a chemical element with the symbol I and atomic number 53.  Iodine is a trace element that is naturally present in some foods, is added to some types of salt, and is available as a dietary supplement.

Concept:

As the value of Z (atomic number) increases, the energy of orbitals decreases (becomes more negative value)

The energy of 2s orbital is lowest in K (potassium)

Therefore, the order of energy of 2s orbital is H > Li > Na > K

The correct option is Rubidium.

Key Points

• Rubidium is the chemical element with the symbol Rb and atomic number 37.
• Rubidium is a very soft, whitish-grey metal in the alkali metal group. Rubidium metal shares similarities to Potassium metal and Caesium metal in physical appearance, softness and conductivity.
• Rubidium was discovered in 1861 by Robert Bunsen and Gustav Kirchhoff, in Heidelberg, Germany.
• Rubidium reacts violently with water and can cause fires.
• It is also used in fireworks to give it a purple color.

Additional Information

• Caesium (or cesium) is a chemical element with the symbol Cs and atomic number 55. Its one of only five elemental metal that are liquid at or near room temperature. In 1860, Robert Bunsen and Gustav Kirchhoff discovered caesium.
• Francium is a chemical element with the symbol Fr and atomic number 87. It is extremely radioactive and second rarest naturally occuring element. Francium was discovered by Marguerite Perey in France in 1939.
• Gallium is a chemical element with the symbol Ga and atomic number 31. Discovered by French chemist Paul-Émile Lecoq de Boisbaudran in 1875, Gallium is in group 13 of the periodic table and is similar to the other metals of the group.

The correct answer is Nihonium.Key Points

• The element with atomic number 113 belongs to group 13 of the periodic table, which is also known as the boron group.
• The electronic configuration [Rn] 5f¹⁴6d¹⁰7s²7p¹ belongs to the element Nihonium, which was officially named in 2016 and is a synthetic element that is not found naturally on Earth.
• Nihonium is a highly unstable and radioactive element, with a very short half-life of only a few seconds, and its properties are still being studied by scientists.

Additional Information

• Group 13 elements are characterized by having three valence electrons in their outermost shell, which makes them reactive and able to form compounds with other elements.
• Gallium is a soft, silvery metal that has a low melting point and is used in a variety of applications, such as in semiconductors, LEDs, and alloys.
• Indium is a rare, silvery-white metal that is used in electronics, as well as in coatings, alloys, and other industrial applications.
• Thallium is a toxic, bluish-white metal that is used in electronics, as well as in pesticides, rodenticides, and other chemicals.
• It is also a radioactive isotope that is used in medical imaging.
• Thallium is also a group 13 element, but it has a higher atomic number than Nihonium and a different electronic configuration.

Concept:

• Nuclear charge: The nuclear charge is the total charge of all the protons in the nucleus.

Nuclear charge of Boron (B) > Nuclear charge of Be

First ionization enthalpy:

Be = 1s² 2s² (more stable)

B = 1s² 2s² 2p¹

The first ionization of Beryllium is greater than that of boron because beryllium has a stable complete electronic configuration (1s² 2s²) so it requires more energy to remove the first electron from it. Whereas boron has the electronic configuration 1s² 2s² 2p¹ which needs lesser energy than that of beryllium to remove the valence electron.

∴ Ionisation energy of Be is greater than B due to ns² outer electronic configuration.

The ionization energy is the energy required to remove an electron from its orbital around an atom to a point where it is no longer associated with that atom. The ionization energy of an element increases as one moves across the period in the periodic table because the electron is held tighter by the higher effective nuclear charge.

The correct answer is Li and Mg. Key Points

• Lithium (Li) and Magnesium (Mg) show a diagonal relationship as they are located diagonally opposite to each other in the periodic table.
• Both Li and Mg have similar atomic radii, electronegativities, and ionization energies due to the similarities in their electronic configurations.
• A diagonal relationship refers to the similarities in properties between elements that are diagonally opposite to each other in the periodic table.

Additional Information

• Diagonal relationship is a result of the similarities in the electronic configurations of these elements.
• Be and B do not show a diagonal relationship as they are not located diagonally opposite to each other in the periodic table.
• Similarly, Be and Mg do not show a diagonal relationship as they belong to the same group and have different electronic configurations.
• Na and Mg also do not show a diagonal relationship as they belong to different periods and have different electronic configurations.

Concept: -

• Modern Periodic Table has 18 Groups and 7 Periods.
• It has 118 Elements.
• Each of the tables has a vertical row called a group. Elements in groups have similar chemical and physical properties because they have the same number of outer electrons.
• Each of the tables has horizontal rows called periods. During a period, a gradual change in chemical properties occurs from one element to another.
• The elements are arranged in the modern periodic table on the basis of Mosely's law, which states that the physical and chemical properties of elements are the periodic function of their atomic number.
• The Structure of it is like a bird Grid.
• The Modern Periodic table is used to organize all the known elements.
• Advantages of Modern Periodic Table:- 
  • It is easier to remember the properties of an element if its position in the periodic table is known.
  • It made the study of Chemistry Systematic and Easy.

Modern Periodic Table:-

Explanation: -

A period in the periodic table represents the principal quantum number.

As Principal quantum numbers stay the same moving left to right in the rows of the periodic table.

So, the shell remains same in a periodic table, while moving from left to right in a period.

Hence, the correct answer is a shell, option 3.

Concept:

The pair that has similar atomic radii is Mo and W because Mo and W belong to group-6 and period-5 (4d series), period-6 (5d series) respectively, Due to the lanthanoid contraction, the radius of Mo and W are almost the same i.e. 0.140 nm and 0.141 nm respectively.

Lanthanoid contraction is the steady decrease in the size of the atoms and ions of the rare earth elements with increasing atomic number from lanthanum (atomic number 57) through lutetium (atomic number 71).

Molybdenum (Mo) is a chemical element with the symbol Mo and atomic number 42.

Molybdenum does not occur naturally as a free metal on Earth, it is found only in various oxidation states in minerals. The free element, silvery metal with a grey cast, has the sixth-highest melting point of any element. It readily forms hard, stable carbides in alloys.

Tungsten or wolfram is a chemical element with the symbol W and atomic number 74. Tungsten is a rare metal found naturally on Earth almost exclusively combined with other elements in chemical compounds rather than alone. Its important ores include wolframite and scheelite.