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Dεερακ Ȿιηɠꜧ 5 years, 1 month ago
Yogita Ingle 5 years, 1 month ago
These are Properties of anode rays as under:
(i) They consist of Positively charged particles. Their mass is virtually the same as that of the atoms from which they are derived and is found to be equal to the atomic mass of the gas in the discharge tube.
(ii)They travel in straight lines.
(iii)They are capable of producing physical and chemical changes.
(iv) They can penetrate thin metal foils.
(v)They can produce ionization in gases.
(vi)They are deflected by electrical and magnetic fields just as the cathode rays but in opposite directions showing that they are oppositely charged, i.e., they carry positive charge. Since their deflection is very little, they consist of very heavy particles.
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Yogita Ingle 5 years, 1 month ago
Atomic or molecular chemical species having a highly localized HOMO (The Highest Occupied Molecular Orbital) act as Lewis bases. These chemical species have the ability to donate an electron pair to a given Lewis acid in order to form an adduct, as discussed earlier.
Examples of Lewis bases which have an ability to donate an electron pair are listed below.
- Pyridine and the derivatives of pyridine have the ability to act as electron pair donors. Thus, these compounds can be classified as Lewis bases.
- The compounds in which Oxygen, Sulphur, Selenium, and Tellurium (which belong to group 16 of the Periodic Table) exhibit an oxidation state of -2 are generally Lewis bases. Examples of such compounds include water and ketones.
- The simple anions which have an electron pair can also act as Lewis bases by donating these electrons. Examples of such anions include H– and F–. Even some complex anions, such as the sulfate anion (SO42-) can donate pairs of electrons.
Posted by Sidharth ($Id) 5 years, 1 month ago
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Royal Thakur ? 5 years, 1 month ago
Yogita Ingle 5 years, 1 month ago
Lewis Acids are the chemical species which have empty orbitals and are able to accept electron pairs from Lewis bases. This term was classically used to describe chemical species with a trigonal planar structure and an empty p-orbital. An example of such a Lewis acid would be BR3 (where R can be a halide or an organic substituent).
Some common examples of Lewis acids which can accept electron pairs include:
- H+ ions (or protons) can be considered as Lewis acids along with onium ions like H3O+.
- The cations of d block elements which display high oxidation states can act as electron pair acceptors. An example of such a cation is Fe3+.
- Cations of metals such as Mg2+ and Li+ can form coordination compounds with water acting as the ligand. These aquo complexes can accept electron pairs and behave as Lewis acids.
Posted by Kajal Verma 5 years, 1 month ago
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Gaurav Seth 5 years, 1 month ago
Molarity is dependent on temperature.
Molarity = number of moles of solute / volume of solution in L
The number of moles of solute is independent of temperature.
The volume of the solution is dependent on temperature.
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Dεερακ Ȿιηɠꜧ 5 years, 1 month ago
Dεερακ Ȿιηɠꜧ 5 years, 1 month ago
Thus, 100 g of iron oxide contains 69.9 g iron and 30.1 g dioxygen.
The number of moles of iron present in 100 g of iron oxide are $$55.8/69.9=1.25$$. The number of moles of dioxygen present in 100 g of iron oxide are $$32/30.1=0.94$$. The ratio of the number of oxygen atoms to the number of carbon atoms present in one formula unit of iron oxide is $$1.252×0.94=1.5:1=3:2$$. Hence, the formula of the iron oxide is $$Fe2O3$$
Aadya Singh 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
The electronic configuration of Zinc is 1s2,2s2,2p6,3s2,3p6,4s2,3d10.
Posted by Praneeth Reddy 5 years, 1 month ago
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Yogita Ingle 5 years, 1 month ago
Transition elements : The elements which have plenty filled d - subshells are known as d - block elements . These elements are lying between S and P - block elements. They represnt transition transition (change) in properties from strongly electropositive and metallic character of S - block elements to electronegative and non-metallic character of P - block elements, i.e. their properties are inter-mediate to those of S - block and P - block elements.
Four characteristic properties of transition metals.
- They are hard, heavy and less reactive metals.
- They show variable valencies.\
- They give coloured ions.
- They have high tendency to form complex compounds.
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Yogita Ingle 5 years, 1 month ago
Dalton’s law of partial pressures is a gas law which states that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures exerted by each individual gas in the mixture. For example, the total pressure exerted by a mixture of two gases A and B is equal to the sum of the individual partial pressures exerted by gas A and gas B (as illustrated below).
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Yogita Ingle 5 years, 1 month ago
Reduction
Reduction is defined as the memoval of oxygen/electronegative element from a substance or addition of hydrogen or electropositive element to a substance.
For example,
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Sayali Chorage 5 years, 1 month ago
Yogita Ingle 5 years, 1 month ago
Oxidation is defined as the addition of oxygen/electronegative element to a substance or rememoval of hydrogen/ electropositive element from a susbtance.
For example,
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Yogita Ingle 5 years, 1 month ago
The common oxidation state of group 16 elements is +2, +4, +6.
The group 16 elements, also known as the chalcogens have 6 valence electrons, and hence they can achieve noble gas configuration either by gaining 2 electrons or by sharing two electrons i.e., by forming M2- ions, or forming two covalent bonds. The oxidation state of elements is defined as the number of electrons gained or lost to form a bond and its sign is the indication of ionic charge on the element. Oxygen is the most electronegative element after fluorine. The difference in electronegativity between metals and oxygen is generally very high. We know that ionic bond is formed when the difference in electronegativity of any two elements is very high. Thus, metals and oxygen combine to form a metal oxide with oxygen attaining O2- form, so the oxidation state of oxygen is mostly (-II).
Electronegativity of chalcogens decreases down the group in the periodic table. Other chalcogen elements like sulphur, selenium, and tellurium react with a more electronegative element of group 1, 2 and lanthanides i.e., the uppermost elements of group 1, 2 and lanthanides to form sulphides, selenides, and tellurides. These compounds are the most stable compounds formed by these elements. Compounds formed above can be denoted as S2-, Se2-, and Te2-. The electronegativity difference between the compounds (sulphides, selenides, and tellurides) shows that they are on the borderline of 50% ionic and 50% covalent characters as in the case of PCl5. Phosphorus pentachloride is sometimes covalent in the solid state but is ionic in the aqueous state.
The chalcogen group can also share their two electrons with another element to form two covalent bonds for example H2O,F2O,Cl2O,H2S and SCl2. In the given examples the chalcogen elements have the least electronegativity. As we can see in the case of SCl2 (the electronegativity of chlorine = 3.5 and sulphur =2.5) and the oxidation state of sulphur is (+II).
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Yogita Ingle 5 years, 1 month ago
The metals always have oxidation number in positive and non metal in negative when present together in ionic compounds.
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