Group 17 Elements (Halogens Family) MCQ Quiz in मल्याळम - Objective Question with Answer for Group 17 Elements (Halogens Family) - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

The correct answer is Sea.

Key Points

• Out of the options, the greatest source of halogens is Sea.
  • Halogens are a group of elements in the periodic table that include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).
  • These elements are very reactive and don't often occur in their pure form in nature.
  • Instead, they are commonly found combined with other elements, predominantly as salts dissolved in seawater.
  • Seawater: Contains large amounts of dissolved salts, including sodium chloride (NaCl), magnesium chloride (MgCl₂), and potassium chloride (KCl).
    • These salts release chloride (Cl) and, to a lesser extent, bromide (Br) and iodine (I) when dissolved in water.

Additional Information

• Lake water: While it also contains dissolved salts, the concentration of halogens in lakes is generally much lower than in seawater.
• Emissions from automobiles: Although car exhaust might contain trace amounts of certain halogens like chlorine from combustion or brake pads, it's not a significant source compared to the vast reservoirs in seawater.
• Facts about halogens:
  • They play crucial roles in various biological processes, like thyroid function in humans.
  • Some halogens have industrial applications, like chlorine in disinfecting water and bromine in flame retardants.
  • Due to their high reactivity, halogens can also be harmful if not handled properly.

The correct answer is I Key Points

• The electron affinity of halogens is the energy change that occurs when an electron is added to a neutral atom to form a negative ion.
• The correct order of electron affinity of halogens is I
• This is because as we move down the group, the atomic radius increases, and the distance between the nucleus and the valence electrons increases, leading to a decrease in the attraction between the nucleus and the added electron.

Additional Information

• The chemical element iodine has the atomic number 53 and the symbol I.
  • The heaviest stable halogen, it is a semi-lustrous, non-metallic solid at ordinary circumstances.
• At normal temperature, bromine is a naturally occurring liquid element.
  • It dissolves in water and has a brownish-red color and bleach-like smell.
• The chemical element fluorine has an atomic number of nine and the symbol F.
  • Fluorine is a gas at room temperature and is categorized as a halogen.
• The chemical element chlorine has the atomic number 17 and the symbol Cl.
  • The second-lightest of the halogens, it is found on the periodic table between fluorine and bromine, with most of its properties falling in the middle of the two.  

Correct answer: 1)

Concept:

• Lewis structures (also known as Lewis dot structures or electron dot structures) are diagrams that represent the valence electrons of atoms within a molecule.
• These Lewis symbols and Lewis structures help visualize the valence electrons of atoms and molecules, whether they exist as lone pairs or within bonds.

Explanation:

• When we draw a Lewis dot structure of I^3- (triiodide ion, which is linear), we see that the central I-atom forms two bonds, and has three non-bonding pairs of electrons.

• That's a total of five electron pairs - more than an octet.
• Many compounds violate the octet rule in this way, but the first long-row elements like F can't.
• The reason is that the elements with higher atomic numbers like iodine can use an available d-orbital to accommodate the additional pair of electrons (sp³d hybridization).
• On the other hand, in the case of fluorine, due to the non-availability of d-orbitals in the valence shell it cannot expand its octet and hence cannot form F₃- ion.

Conclusion:

• Hence, Iodine can readily form I3-  but Fluorine cannot form F3- because fluorine has no vacant d orbitals available in its valence shell.

Correct answer: 1)

Concept:

• Lewis structures (also known as Lewis dot structures or electron dot structures) are diagrams that represent the valence electrons of atoms within a molecule.
• These Lewis symbols and Lewis structures help visualize the valence electrons of atoms and molecules, whether they exist as lone pairs or within bonds.

Explanation:

• When we draw a Lewis dot structure of I^3- (triiodide ion, which is linear), we see that the central I-atom forms two bonds, and has three non-bonding pairs of electrons.

• That's a total of five electron pairs - more than an octet.
• Many compounds violate the octet rule in this way, but the first long-row elements like F can't.
• The reason is that the elements with higher atomic numbers like iodine can use an available d-orbital to accommodate the additional pair of electrons (sp³d hybridization).
• On the other hand, in the case of fluorine, due to the non-availability of d-orbitals in the valence shell it cannot expand its octet and hence cannot form F₃- ion.

Conclusion:

• Hence, Iodine can readily form I3-  but Fluorine cannot form F3- because fluorine has no vacant d orbitals available in its valence shell.

Correct answer: 1)

Concept:

• Lewis structures (also known as Lewis dot structures or electron dot structures) are diagrams that represent the valence electrons of atoms within a molecule.
• These Lewis symbols and Lewis structures help visualize the valence electrons of atoms and molecules, whether they exist as lone pairs or within bonds.

Explanation:

• When we draw a Lewis dot structure of I^3- (triiodide ion, which is linear), we see that the central I-atom forms two bonds, and has three non-bonding pairs of electrons.

• That's a total of five electron pairs - more than an octet.
• Many compounds violate the octet rule in this way, but the first long-row elements like F can't.
• The reason is that the elements with higher atomic numbers like iodine can use an available d-orbital to accommodate the additional pair of electrons (sp³d hybridization).
• On the other hand, in the case of fluorine, due to the non-availability of d-orbitals in the valence shell it cannot expand its octet and hence cannot form F₃- ion.

Conclusion:

• Hence, Iodine can readily form I3-  but Fluorine cannot form F3- because fluorine has no vacant d orbitals available in its valence shell.

Concept:

• Acids: According to Bronsted-Lowry theory, an acid is any substance that can donate a proton (H⁺). It is also known as a proton donor. 

​                     For example, HCl → H⁺ + Cl^- 

           HCl loses a proton to give Cl^- ions, hence it is an acid.

• Acids are classified as strong acids and weak acids based on their degree of dissociation. Strong acids are almost completely dissociated in water whereas weak acids are partially dissociated in water. The extent of the acids' dissociation depends on the compound's bond strength and bond dissociation energy.
• Bond dissociation energy is the energy required to break the bond and gives a measure of the bond's strength. Stronger the bond, the more the bond dissociation energy.

Explanation:

• Halogens (F, Cl, Br, I) carry very high values of electronegativities due to their small atomic radii and high effective charge. As we go down the group, the electronegativity values decrease from Fluorine to Iodine.
• Given below are the values of electronegativities of halogens.

​

• All halogens form protic molecular hydrides or hydrogen halides (HX). 
• Due to the trend in electronegativities, HF has the strongest bond and will require the maximum energy to break the bond to release the proton. Hence, HF is the weakest acid as compared to other hydrogen halides. ​ 

• Therefore, the acidic strength of the halogen halides varies in the order:

           HF

Conclusion:

The increasing order of acidity of hydrogen halides is HF due to the decrease in the bond dissociation energy.