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Questions and Answers
Which factor most influences the variation in properties among p-block elements?
Which factor most influences the variation in properties among p-block elements?
- Atomic mass of the element
- Number of neutrons in the nucleus
- Number of protons in the nucleus
- The presence of d and f electrons in the inner core (correct)
The maximum oxidation state exhibited by a p-block element is always equal to the group oxidation state.
The maximum oxidation state exhibited by a p-block element is always equal to the group oxidation state.
False (B)
What electronic configuration change explains the trend toward metallic character moving down a p-block group?
What electronic configuration change explains the trend toward metallic character moving down a p-block group?
The non-metallic character of elements decreases down the group as the heaviest element in each p-block group is the most metallic in nature.
The first member of a p-block group differs from subsequent members due to its ______ and the absence of d-orbitals.
The first member of a p-block group differs from subsequent members due to its ______ and the absence of d-orbitals.
Match each element with its typical characteristic:
Match each element with its typical characteristic:
What is the most abundant metal in the Earth's crust found in Group 13 elements?
What is the most abundant metal in the Earth's crust found in Group 13 elements?
The atomic radius of Gallium is larger than that of Aluminum due to increased nuclear charge.
The atomic radius of Gallium is larger than that of Aluminum due to increased nuclear charge.
What phenomenon explains the ionization enthalpy discontinuity observed between Aluminum and Gallium?
What phenomenon explains the ionization enthalpy discontinuity observed between Aluminum and Gallium?
The inert pair effect results from the tight holding of ______ electrons due to poor shielding effects of intervening d and f orbitals.
The inert pair effect results from the tight holding of ______ electrons due to poor shielding effects of intervening d and f orbitals.
Match each element oxide with its acid-base property:
Match each element oxide with its acid-base property:
Which of the following statements is accurate regarding Group 13 elements and their behavior as Lewis acids?
Which of the following statements is accurate regarding Group 13 elements and their behavior as Lewis acids?
Aluminum reacts with concentrated nitric acid due to its high activity.
Aluminum reacts with concentrated nitric acid due to its high activity.
Explain why Boron is unable to form $BF_6^{3-}$ ion.
Explain why Boron is unable to form $BF_6^{3-}$ ion.
Borax contains tetranuclear units with the formula $[B_4O_5(OH)4]^{_____}$.
Borax contains tetranuclear units with the formula $[B_4O_5(OH)4]^{_____}$.
Match each form of carbon with its structural characteristic:
Match each form of carbon with its structural characteristic:
What property of carbon is responsible for the vast diversity of organic compounds?
What property of carbon is responsible for the vast diversity of organic compounds?
The tendency to undergo catenation increases down the group 14 elements.
The tendency to undergo catenation increases down the group 14 elements.
How does silicon dioxide react with HF, and how does this inform its applications?
How does silicon dioxide react with HF, and how does this inform its applications?
Silicones are organosilicon polymers with the repeating unit ______.
Silicones are organosilicon polymers with the repeating unit ______.
Match each carbon compound with its respective characteristic property or application:
Match each carbon compound with its respective characteristic property or application:
Flashcards
p-Block Electronic Configuration
p-Block Electronic Configuration
The outer shell electronic configuration for p-block elements is ns² np¹⁻⁶ (except for Helium).
Inert Pair Effect
Inert Pair Effect
The ‘inert pair effect’ is the non-participation of the ns² electrons in bonding, making lower oxidation states more stable for heavier elements.
Non-Metal Ion Formation
Non-Metal Ion Formation
Non-metals have higher ionization enthalpies and electronegativities, thus readily forming anions.
Boron's Maximum Covalence
Boron's Maximum Covalence
Boron's maximum covalence is four due to the absence of d orbitals.
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Electron Deficient Behaviour
Electron Deficient Behaviour
Electron deficient molecules have a tendency to accept a pair of electrons and behave as Lewis acids.
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Borax Formula
Borax Formula
Borax is a white crystalline solid with the formula Na₂B₄O₇·10H₂O, containing tetranuclear units [B₄O₅(OH)₄]²⁻.
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Diborane Bonding
Diborane Bonding
Diborane (B₂H₆) contains two bridging hydrogen atoms, described by 3-centre-2-electron bonds.
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Uses of Boron Fibres
Uses of Boron Fibres
Boron fibres are used in making bullet-proof vests and making composite materials for aircrafts.
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Catenation
Catenation
The tendency of atoms to link with each other through covalent bonds to form chains and rings is called catenation.
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Carbon’s Catenation Property
Carbon’s Catenation Property
Carbon exhibits the property catenation due to strong carbon to carbon bonds.
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Fullerenes
Fullerenes
Fullerenes, discovered in 1985, are allotropes of carbon with a spherical structure and without dangling bonds.
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Carbon Monoxide Formation
Carbon Monoxide Formation
Heating carbon with limited supply of oxygen yields carbon monoxide.
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Silicon reactivity
Silicon reactivity
At normal conditions almost all silicon is non-reactive, but is attacked with HF and NaOH.
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What are SILICONES?
What are SILICONES?
Silicones consist of -O-Si-O- chains in which alkyl or phenyl groups occupy the remaining bonding positions on each silicon. They can be water repellant
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Zeolites formation
Zeolites formation
In zeolites, if aluminium atoms replace few silicon atoms in 3D network of Silicon Dioxide, the overall structure is called aluminosilicate.
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- The chemistry of p-block elements is made interesting by the influence of d and f electrons in the inner core of heavier elements
General Trends
- Group 13-18
- Last electron is in the outermost p orbital
- There are 3 p orbitals
- Maximum of 6 electrons in the p orbitals
- Valence shell electronic configuration is ns²np¹⁻⁶ (except He)
- Inner core electronic configuration varies
- The difference in inner core configurations impacts physical and chemical properties
- Observed variations exist in the properties of elements in the p-block group
- The maximum oxidation state of a p-block element equals the total valence electrons
Oxidation States
- Possible oxidation states increase to the right of the periodic table
- p-block elements can show other oxidation states that differ by a unit of two from the total valence electrons
- Boron, carbon, and nitrogen families see the group oxidation state as most stable for lighter elements in the group
- The oxidation state at two units less than the group oxidation state becomes progressively more stable for heavier elements in each group
- Occurrence of oxidation states at two units less than the group oxidation is attributed to the inert pair effect
Trends and Variations
- Non-metals and metalloids are exclusive to the p-block
- The non-metallic nature of elements decreases down the group
- Heaviest element in each p-block group is most metallic
- Non-metals generally exhibit higher ionization enthalpies and electronegativities than metals
- Highly reactive non-metals form anions, while metals readily form cations
- Compounds between highly reactive non-metals and metals tend to be ionic due to electronegativity differences
- Compounds formed between non-metals tend to be covalent due to small electronegativity differences
- Non-metal oxides are acidic or neutral, whereas metal oxides are basic
Unique Behavior of First Members
- First p-block member differs from remaining members of the group in size and all size-dependent properties
- Lightest p-block elements differ similarly to lithium and beryllium
- The effect of d-orbitals in the valence shell of heavier elements, starting from the third period, is another difference
- Second-period p-group elements from boron, have a maximum covalence of four, utilizing 2s and three 2p orbitals
- The third-row elements of p-groups with 3s²3pⁿ electronic configuration have vacant 3d orbitals between the 3p and 4s energy levels
- The elements of the third period have covalence above four by using d-orbitals
- Boron forms only [BF₄]⁻, while aluminium forms [AlF₆]³⁻
- Size and availability of d orbitals influence the ability of these elements to form π bonds
- First members differ in ability to form pπ-pπ multiple bonds
- Heavier elements can form π bonds, but involve d orbitals (dπ-pπ or dπ-dπ)
- The heavier elements form weaker π bonds, d orbitals have higher energy levels
- Coordination number of heavier elements may be higher than the first element in the same oxidation state
Group 13 Elements: Boron Family
- This group exhibits variation in properties
- Boron is a non-metal
- Aluminum is a metal with chemical similarities to boron
- Gallium, indium, and nihonium are exclusively metallic
Boron
- Boron is a rare element
- It mainly exists as orthoboric acid (H₃BO₃), borax (Na₂B₄O₇·10H₂O), and kernite (Na₂B₄O₇·4H₂O)
- Borax is found in Puga Valley, Ladakh and Sambhar Lake, Rajasthan in India
- Earth's crust abundance is less than 0.0001% by mass
- Two isotopic forms exist: Boron-10 (19%) and Boron-11 (81%)
Aluminium
- Aluminum is the most abundant metal with 8.3% by mass of the Earth's crust
- Bauxite (Al₂O₃·2H₂O) and cryolite (Na₃AlF₆) are the main minerals of aluminum
- Aluminum is found as mica in Madhya Pradesh, Karnataka, Orissa and Jammu in India
Gallium, Indium, and Thallium
- Gallium, indium, and thallium are less abundant
Nihonium
- Element with symbol Nh, atomic number 113, and atomic mass 286 g/mol
- Electronic configuration is [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p¹
- Synthetically prepared in small amounts
- Half-life of the most stable isotope is 20 seconds
- Chemistry has not been established
- Nihonium is a synthetic radioactive element
Electronic Configuration (Group 13)
- Outer configuration is ns²np¹
- Boron and aluminum have noble gas cores
- Gallium and indium include noble gas plus 10 d-electrons
- Thallium includes noble gas plus 14 f-electrons plus 10 d-electrons
- Differences in electronic structures affect other properties and the chemistry of the elements
Atomic Radii
- Atomic radius typically increased down the group as more electron shells are added
- Gallium's atomic radius is less than aluminum due to variance of inner core electronic configuration
- 10 d-electrons offers poor screening effects
- Atomic radius of gallium is 135 pm, which is less than aluminum's 143 pm
Ionization Enthalpy
- Ionization enthalpy does not decrease smoothly
- The first Ionization enthalpy decreases from B to Al related to increasing size
- Ionization enthalpy values between Al and Ga, and In and Tl are discontinuous
- These are due to weak screening by d- and f-electrons
- Weak screening fails to compensate for the increase in nuclear charge
- The order of ionization enthalpies is ΔᵢH₁ < ΔᵢH₂ < ΔᵢH₃
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