P Block Board Flashcards
(126 cards)
1
Q
What is the general electronic configuration of Group 16 elements?
A
ns2np4
Group 16 elements are also known as the oxygen family or chalcogens.
2
Q
What is the first element of Group 16?
A
Oxygen (O)
Oxygen is atomic number 8.
3
Q
What is the first element of Group 17?
A
Fluorine (F)
Fluorine is atomic number 9.
4
Q
What is the first element of Group 18?
A
Helium (He)
Helium is atomic number 2.
5
Q
What are the elements of Group 17 collectively known as?
A
Halogens
The term ‘halogen’ comes from Greek, meaning ‘salt-producing’.
6
Q
Why are halogens highly reactive?
A
Due to high electronegativities
Halogens are not found in free state but occur in compounds.
7
Q
What is the most abundant element on Earth?
A
Oxygen
Oxygen makes up 20.95% by volume of air and about 46.6% by mass of the Earth’s crust.
8
Q
What are other names for group 16 elements
A
- Oxygen family
- Chalcogens
Group 16 elements include sulfur, selenium, tellurium, and polonium.
9
Q
What is the electronic configuration of noble gases in Group 18?
A
ns2np6
This configuration indicates a stable electronic arrangement.
10
Q
What is the trend in atomic and ionic radii within Groups 16, 17, and 18?
A
Increase down the group
This is due to an increase in the number of quantum shells.
11
Q
How does ionization enthalpy change across a period?
A
Increases with increasing atomic number
This is due to increased effective nuclear charge.
12
Q
What is the trend in electronegativity within Groups 16, 17, and 18?
A
Decreases down the group
Electronegativity reflects the ability of an atom to attract electrons.
13
Q
What is the electron gain enthalpy trend in Groups 16 and 17?
A
Becomes less negative down the group
This trend indicates a decrease in the tendency to accept electrons.
14
Q
Why does oxygen have less negative electron gain enthalpy than sulfur?
A
Smaller atomic size
Smaller size leads to higher electron-electron repulsion.
15
Q
What is the bond dissociation enthalpy order of halogen molecules?
A
- Cl - Cl >
- Br - Br >
- F - F >
- I - I
This order is due to the strength of the bonds influenced by atomic size.
16
Q
What phase are fluorine and chlorine at room temperature?
A
Gases
Bromine is a liquid and iodine is a solid at room temperature.
17
Q
What is the atomic radius of oxygen?
A
66 pm
This is the atomic radius of oxygen in picometers.
18
Q
What is the ionization enthalpy of fluorine?
A
1680 kJ/mol
Fluorine has the highest ionization enthalpy among the halogens.
19
Q
What is the melting point trend of elements in Groups 16, 17, and 18?
A
Increases with increasing atomic number
This trend is influenced by the strength of intermolecular forces.
20
Q
What type of elements are selenium and tellurium classified as?
A
Metalloids
They have properties of both metals and nonmetals.
21
Q
What is the significance of the half-life of polonium?
A
Radioactive element with a half-life of 13.8 days
Polonium is a decay product of thorium and uranium.
22
Q
What is the electron gain enthalpy of fluorine compared to chlorine?
A
Less negative
Fluorine’s small size causes stronger electron-electron repulsion.
23
Q
What is lone pair-lone pair repulsion?
A
Repulsion that occurs between non-bonding pairs of electrons in a molecule
This concept is important in molecular geometry and affects the shape of molecules.
24
Q
What trend is observed in melting and boiling points with increasing atomic number in group 16 elements?
A
Melting and boiling points increase
This trend is due to the increase in van der Waals forces as atomic size increases.
25
Why is there a large difference between the melting and boiling points of oxygen and sulfur?
Oxygen exists as a diatomic molecule (O2), whereas sulfur exists as a polyatomic molecule (S8)
## Footnote
The van der Waals forces are weaker in O2 compared to the stronger forces in S8 due to larger molecular size.
26
What are the characteristics of noble gases?
* Monoatomic
* Sparingly soluble in water
* Very low melting and boiling points
## Footnote
Helium has the lowest boiling point of any known substance at 4.2 K.
27
What causes the low melting and boiling points of noble gases?
They are monoatomic with only van der Waals forces between them
## Footnote
This allows them to be liquefied at very low temperatures.
28
What is the atomicity of oxygen compared to other group 16 elements?
Oxygen is a diatomic molecule (O2), while others are polyatomic
## Footnote
For example, sulfur exists as S8.
29
What is the common covalency of oxygen?
2, but can be 4 in rare cases
## Footnote
Other group 16 elements can exceed a covalency of four.
30
What are the reasons for the anomalous behavior of oxygen?
* Small atomic size
* High electronegativity
* Absence of inner d-orbitals
## Footnote
These factors influence its chemical behavior compared to other group 16 elements.
31
What distinguishes the oxidation states of oxygen from those of other group 16 elements?
Oxygen shows -2, -1, and +2 oxidation states, while others show -2, +2, +4, +6
## Footnote
Oxygen cannot exhibit higher oxidation states due to the absence of vacant d orbitals.
32
What is the trend in oxidation states for group 17 elements?
Halogens exhibit -1 oxidation state; Cl, Br, I can also show +1, +3, +5, +7 due to empty d-orbitals
## Footnote
Fluorine only exhibits -1 due to its high electronegativity.
33
What is the stability trend of halides?
Fluorides > Chlorides > Bromides > Iodides
## Footnote
This trend is influenced by bond strength and electronegativity.
34
What type of compounds do group 16 elements form with hydrogen?
Hydrides of the type H2E
## Footnote
Where E represents elements like O, S, Se, Te, Po.
35
What is the acidic strength trend of hydrogen halides?
HF < HCl < HBr < HI
## Footnote
This order is due to decreasing bond dissociation enthalpy.
36
What are the properties of the hydrides of group 16 elements?
* H2O is colorless and odorless
* H2S, H2Se, H2Te, and H2Po are colorless gases with bad odors
* Weakly acidic
## Footnote
The acidic character increases down the group.
37
What is the reactivity of group 18 elements towards hydrogen?
Noble gases are chemically inert due to their stable electronic configuration
## Footnote
They do not form hydrogen halides.
38
What type of oxides do group 16 elements form?
* EO2
* EO3
## Footnote
Where E represents elements like S, Se, Te, Po.
39
What is the property of fluorine oxides?
Fluorine forms two oxides OF2 and O2F2, with OF2 being thermally stable
## Footnote
Both are strong fluorinating agents.
40
How do group 17 elements react with halogens?
They form interhalogen compounds of types XX', XX'5, and XX'7
## Footnote
Where X is a larger halogen and X' is a smaller halogen.
41
What is the significance of d-orbitals in xenon?
Xenon can exhibit higher oxidation states due to the presence of d-orbitals
## Footnote
This allows for the formation of covalent compounds with fluorine or oxygen.
42
What is the general formula for the reaction of group 17 elements with hydrogen?
H2 + X2 → 2HX
## Footnote
Where X represents halogens such as F, Cl, Br, and I.
43
What is the photocopying process?
A selenium-coated rotating drum is given a uniform positive charge, exposed to an image, negatively charged toner particles are attracted, and the image is transferred to paper and fixed by heating.
## Footnote
The drum is then cleaned and prepared for another cycle.
44
What do elements of group 17 (Halogens) react with metals to form?
Metal halides
## Footnote
Example: 2Na (s) + Cl2 (g) → 2NaCl (s)
45
What is the order of ionic character of halides?
MF > MCl > MBr > MI
## Footnote
M is a monovalent metal.
46
How does the oxidation state of metals affect the covalent character of metal halides?
Higher oxidation states lead to more covalent character.
## Footnote
Example: SnCl4 is more covalent than SnCl2.
47
Do noble gases (Group 18) directly react with metals?
No
## Footnote
Noble gases are generally inert.
48
What is allotropy?
The existence of an element in more than one form in the same physical state.
## Footnote
Example: Oxygen has O2 and O3.
49
What is the difference between allotropy and polymorphism?
Allotropy refers to different forms of an element, while polymorphism refers to different forms of a compound.
## Footnote
Both concepts involve variations in structure.
50
What are the allotropes of sulfur?
Rhombic sulfur (α-sulfur) and monoclinic sulfur (β-sulfur)
## Footnote
Both are non-metallic and have distinct properties.
51
Which allotrope of sulfur shows paramagnetic behavior?
S2 molecule in vapor state
## Footnote
It has two unpaired electrons.
52
What are the two allotropic forms of selenium?
Red (non-metallic) and grey (metallic)
## Footnote
Each form has different electrical properties.
53
What are the allotropic forms of tellurium?
Crystalline and amorphous
## Footnote
These forms exhibit different physical properties.
54
What is the method of preparation for rhombic sulfur?
Evaporation of roll sulfur in CS2
## Footnote
This results in the formation of orthorhombic crystals.
55
What is the stability temperature for rhombic and monoclinic sulfur?
Rhombic is stable below 369 K; monoclinic is stable above 369 K.
## Footnote
They transform into each other at this temperature.
56
What are oxoacids?
Acids that contain oxygen, hydrogen, and another element.
## Footnote
Sulfur forms several oxoacids, including sulfurous and sulfuric acids.
57
What is the general trend in acid strength of halogen oxoacids?
Acid strength increases with increasing oxidation state of halogen.
## Footnote
Example: HClO (weak) to HClO4 (strong).
58
What is a simple oxide?
A binary compound of oxygen with another element.
## Footnote
Examples include SO2 and Na2O.
59
How can oxides be classified?
Acidic oxides, basic oxides, amphoteric oxides, neutral oxides
## Footnote
Each category has distinct chemical behaviors.
60
What is the chemical behavior of ozone (O3)?
Ozone is a powerful oxidizing agent and can decompose to liberate nascent oxygen.
## Footnote
Ozone oxidizes various substances, including lead sulfide.
61
What is the environmental issue related to ozone depletion?
Increased UV radiation reaching the Earth's surface
## Footnote
This leads to higher rates of skin cancer and eye cataracts.
62
What are the physical properties of dioxygen (O2)?
Colorless, odorless gas, sparingly soluble in water
## Footnote
Used in respiration and industrial applications.
63
What is the paramagnetic nature of dioxygen attributed to?
Presence of two unpaired electrons in molecular orbital theory
## Footnote
This explains its magnetic properties despite having an even number of electrons.
64
What is the preparation method of ozone in the laboratory?
Passing silent electric discharge through pure and dry oxygen
## Footnote
This process yields ozonised oxygen.
65
What is the significance of the ozone layer?
Protects the Earth from harmful ultraviolet (UV) radiation
## Footnote
It is often referred to as the 'ozone umbrella'.
66
What is ozone depletion?
Thinning of ozone layer in upper atmosphere
67
Which regions have the most pronounced ozone layer depletion?
Polar regions, especially over Antarctica
68
What compounds contribute to ozone layer depletion?
Nitrogen oxides and chlorofluorocarbons (CFCs)
69
What is the chemical reaction for ozone decomposition?
NO (g) + O3 (g) → NO2 (g) + O2 (g)
70
What are the health effects of increased UV radiation due to ozone depletion?
* Skin cancer * Eye cataracts * Genetic damage * Immune system damage
71
What is ozonolysis?
Reaction of ozone with unsaturated compounds to form ozonides
72
What happens to ozonides during ozonolysis?
They are decomposed by water or dilute acids to give aldehydes or ketones
73
What is the bleaching property of ozone?
Ozone acts as a good bleaching agent due to its oxidizing nature
74
What is the bond angle in the ozone (O3) molecule?
About 117°
75
What is the structure of sulfur dioxide (SO2)?
Angular with SO bond angle of 119.5°
76
How is sulfur dioxide (SO2) produced from sulfur?
By burning sulfur in air: S(s) + O2(g) → SO2(g)
77
What is the use of sulfur dioxide in the presence of moisture?
Acts as a reducing agent
78
What is the reaction of sulfur dioxide with water and sodium sulfite?
Na2SO3 + H2O(l) + SO2 → 2NaHSO3
79
What is the color and smell of sulfur dioxide?
Colorless gas with a pungent smell
80
What are the uses of sulfur dioxide?
* Refining of petroleum and sugar * Bleaching wool and silk * Disinfectant * Preservative
81
What is the contact process?
Method for manufacturing sulfuric acid involving three steps
82
What is the reaction of concentrated sulfuric acid with sodium chloride?
NaCl + H2SO4 → NaHSO4 + HCl
83
What is the reaction of chlorine with ammonia?
8NH3 + 3Cl2 → 6NH4Cl + N2
84
What is a physical property of chlorine?
Greenish-yellow gas with a pungent odor
85
What happens when chlorine reacts with dry slaked lime?
Produces bleaching powder: 2Ca(OH)2 + 2Cl2 → Ca(OCl)2 + CaCl2 + 2H2O
86
What is the result of reacting chlorine with saturated hydrocarbons?
Gives substitution products
87
What is the reaction of ozone with colored matter?
Coloured matter + O → colourless matter
88
Fill in the blank: Ozone is used for _______.
[air purification, sterilizing drinking water, bleaching, manufacturing chemicals]
89
True or False: Ozone can bleach in the presence of moisture.
True. It is also dry bleach which means it can bleach in absence of moisture
90
What is the oxidation reaction of sulfur dioxide with oxygen?
2SO2(g) + O2(g) → 2SO3(g)
91
What is the dehydrating property of concentrated sulfuric acid?
Removes water from sugar and carbohydrates
92
What type of products do unsaturated hydrocarbons yield when they react with chlorine?
Addition products
## Footnote
This refers to the reaction of unsaturated hydrocarbons like alkenes with chlorine, resulting in the formation of products where chlorine atoms are added across the double bonds.
93
What is the reaction of methane with chlorine in the presence of UV light?
CH4 + Cl2 → CH3Cl + HCl
## Footnote
This reaction shows the substitution of hydrogen in methane with chlorine, producing methyl chloride and hydrogen chloride.
94
What do metals react with chlorine to form?
Chlorides
## Footnote
Metals such as sodium, aluminum, and iron react with chlorine to form their respective metal chlorides.
95
What is the product of the reaction between phosphorus and chlorine?
PCl3
## Footnote
The reaction is represented as P4 + 6Cl2 → 4PCl3.
96
What is the oxidation property of chlorine?
Chlorine oxidizes ferrous salts to ferric salts and sulfites to sulfates.
## Footnote
Examples include the reactions: 2FeSO4 + H2SO4 + Cl2 → Fe2(SO4)3 + 2HCl and Na2SO3 + Cl2 + H2O → Na2SO4 + 2HCl.
97
What is required for chlorine to exhibit bleaching properties?
Presence of moisture (water)
## Footnote
Chlorine liberates nascent oxygen from water, which is responsible for its bleaching action.
98
How is hydrogen chloride prepared in the laboratory?
By heating sodium chloride with concentrated sulfuric acid.
## Footnote
The reaction is NaCl + H2SO4 → NaHSO4 + HCl.
99
What are some uses of chlorine?
* Purification of drinking water
* Bleaching wood pulp
* Extraction of metals like gold and platinum
* Manufacture of dyes, drugs, and organic compounds
* Preparation of poisonous gases
## Footnote
Chlorine is versatile and is used in various industrial processes.
100
What is the solubility behavior of hydrogen chloride in water?
Highly soluble
## Footnote
Hydrogen chloride gas ionizes in water to form hydrochloric acid, indicating its strong acidic nature.
101
What happens when hydrochloric acid reacts with ammonia?
It produces white fumes of ammonium chloride.
## Footnote
The reaction is NH3 + HCl → NH4Cl.
102
What is aqua regia and what is its significance?
A mixture of concentrated HCl and concentrated HNO3 used to dissolve noble metals like gold and platinum.
## Footnote
The reaction is Au + 4H+ + NO3- + 4Cl- → AuCl4- + NO + 2H2O.
103
What are interhalogen compounds?
Compounds formed by the combination of atoms of different halogens.
## Footnote
These compounds exhibit properties intermediate between the halogens involved.
104
What property allows halogens to form interhalogen compounds?
Different electronegativities
## Footnote
This allows halogens to combine, forming compounds with a halogen that has lesser electronegativity.
105
What is the general formula for interhalogen compounds?
XX'n
## Footnote
X is the more electropositive halogen, while X' is the more electronegative halogen.
106
Which halogen has a tendency to form more interhalogen compounds?
Fluorine
## Footnote
Fluorine can combine with all other halogens due to its high electronegativity.
107
What are the states of interhalogen compounds at 25°C?
* ClF: Colorless gas
* BrF: Pale brown gas
* ICl: Ruby red solid (α-form)
* IBr: Black solid
* ClF3: Colorless gas
* BrF3: Yellow-green liquid
* IF3: Yellow powder
## Footnote
These compounds exhibit varying states based on their composition.
108
What is the first true compound of noble gas and who synthesized it?
XeF2, synthesized by Neil Bartlett and Lohman in 1962.
## Footnote
This marked the beginning of known compounds for noble gases, particularly xenon.
109
What are the stable fluorides of xenon?
* XeF2
* XeF4
* XeF6
## Footnote
These compounds are formed under specific conditions of temperature and pressure.
110
How are xenon fluorides generally prepared?
By direct reaction of xenon and fluorine.
## Footnote
The process involves different ratios and conditions like temperature and electric discharge.
111
What is the shape of chlorine trifluoride (ClF3)?
Bent T-shaped
## Footnote
The molecular geometry is influenced by the presence of lone pairs on the chlorine atom.
112
How are xenon fluorides generally prepared?
By direct reaction of xenon and fluorine in different ratios and conditions
## Footnote
Conditions include temperature, electric discharge, and photochemical reaction.
113
What is the product of the reaction between XeF2 and PF5?
XeF2.PF5
## Footnote
This reaction forms adducts.
114
What is the preparation method for xenon trioxide (XeO3)?
3Xe + 5F2 in a sealed Ni tube at 4000°C
## Footnote
This reaction produces XeF2, which then reacts with water.
115
What do xenon fluorides react with to form XeO3?
Water
## Footnote
The reaction is: 3XeF4 + 6H2O → 2Xe + XeO3 + 12HF.
116
What is the oxidation state of xenon in XeF2?
+2
## Footnote
This indicates the formal charge on xenon in this compound.
117
What is the structure of XeF4?
Square planar
## Footnote
The oxidation state of xenon in XeF4 is +4.
118
Which xenon compound has a distorted octahedral structure?
XeF6
## Footnote
The oxidation state of xenon in XeF6 is +6.
119
What is the result of the hydrolysis of XeF2?
4HF + 2Xe + O2
## Footnote
This reaction illustrates the breakdown of XeF2 in the presence of water.
120
Which oxyfluoride of xenon has the formula XeOF2?
Xenon mono oxyfluoride
## Footnote
This compound is derived from partial hydrolysis of xenon fluorides.
121
What happens when XeOF4 reacts with SiO2?
2XeO2F2 + SiF4
## Footnote
This reaction produces xenon dioxydifluoride.
122
What is one use of helium in medical applications?
Mixture of He and O2 is used for artificial breathing of asthma patients
## Footnote
Helium is essential for creating a breathable atmosphere in certain medical situations.
123
What are two uses of neon?
In neon discharge lamps and signs, and in fluorescent tubes
## Footnote
Neon signs are visible from long distances and in mist or fog.
124
What is the primary industrial use of argon?
Producing inert atmosphere in welding and steel production
## Footnote
Argon is crucial for preventing oxidation during these processes.
125
Fill in the blank: The reaction of XeF6 with water yields _______.
XeOF4 + 2HF
## Footnote
This reaction highlights the hydrolytic behavior of xenon fluorides.
126
What is the oxidation state of xenon in XeO3?
+6
## Footnote
This oxidation state is significant in understanding the reactivity and properties of the compound.
