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कर्नाटक बोर्ड पी.यू.सी.पीयूसी विज्ञान 2nd PUC Class 12

Why is the highest oxidation state of a metal exhibited in its oxide or fluoride only?

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प्रश्न

Why is the highest oxidation state of a metal exhibited in its oxide or fluoride only?

अति संक्षिप्त उत्तर
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उत्तर

Due to its small size and high electronegativities, oxygen or fluorine elements can oxidize the metal to its higher oxidation state.

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पाठ 4: The d-block and f-block Elements - Intext Question [पृष्ठ १०१]

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एनसीईआरटी Chemistry Part 1 and 2 [English] Class 12
पाठ 4 The d-block and f-block Elements
Intext Question | Q 4.6 | पृष्ठ १०१

संबंधित प्रश्‍न

Explain why is Fe3+ more stable than Fe2+?


In 3d series (Sc to Zn), which element has the lowest enthalpy of atomisation and why?


An antifriction alloy made up of antimony with tin and copper, which is extensively used in machine bearings is called _______.

(A) Duralumin

(B) Babbitt metal

(C) Spiegeleisen

(D) Amalgam


Write the factors which are related to the colour of transition metal ions.


Give reasons: Sc3+ is colourless in aqueous solution whereas Ti3+ is coloured.


Explain why Zn2+ salts are white whereas Cu2+ salts are coloured.


Assertion: The highest oxidation state of osmium is +8.

Reason: Osmium is a 5d-block element.


Answer the following question:

Which element of the first transition series has highest third ionisation enthalpy?


Mention the type of compounds formed when small atoms like H, C and N get trapped inside the crystal lattice of transition metals. Also give physical and chemical characteristics of these compounds.


A violet compound of manganese (A) decomposes on heating to liberate oxygen and compounds (B) and (C) of manganese are formed. Compound (C) reacts with KOH in the presence of potassium nitrate to give compound (B). On heating compound (C) with conc. \[\ce{H2SO4}\] and \[\ce{NaCl}\], chlorine gas is liberated and a compound (D) of manganese along with other products is formed. Identify compounds A to D and also explain the reactions involved.


Read the passage given below and answer the following question.

Are there nuclear reactions going on in our bodies?

There are nuclear reactions constantly occurring in our bodies, but there are very few of them compared to the chemical reactions, and they do not affect our bodies much. All of the physical processes that take place to keep a human body running are chemical processes. Nuclear reactions can lead to chemical damage, which the body may notice and try to fix. The nuclear reaction occurring in our bodies is radioactive decay. This is the change of a less stable nucleus to a more stable nucleus. Every atom has either a stable nucleus or an unstable nucleus, depending on how big it is and on the ratio of protons to neutrons. The ratio of neutrons to protons in a stable nucleus is thus around 1 : 1 for small nuclei (Z < 20). Nuclei with too many neutrons, too few neutrons, or that are simply too big are unstable. They eventually transform to a stable form through radioactive decay. Wherever there are atoms with unstable nuclei (radioactive atoms), there are nuclear reactions occurring naturally. The interesting thing is that there are small amounts of radioactive atoms everywhere: in your chair, in the ground, in the food you eat, and yes, in your body.

The most common natural radioactive isotopes in humans are carbon-14 and potassium-40. Chemically, these isotopes behave exactly like stable carbon and potassium. For this reason, the body uses carbon-14 and potassium-40 just like it does normal carbon and potassium; building them into the different parts of the cells, without knowing that they are radioactive. In time, carbon-14 atoms decay to stable nitrogen atoms and potassium-40 atoms decay to stable calcium atoms. Chemicals in the body that relied on having a carbon-14 atom or potassium-40 atom in a certain spot will suddenly have a nitrogen or calcium atom. Such a change damages the chemical. Normally, such changes are so rare, that the body can repair the damage or filter away the damaged chemicals.

The natural occurrence of carbon-14 decay in the body is the core principle behind carbon dating. As long as a person is alive and still eating, every carbon-14 atom that decays into a nitrogen atom is replaced on average with a new carbon-14 atom. But once a person dies, he stops replacing the decaying carbon-14 atoms. Slowly the carbon-14 atoms decay to nitrogen without being replaced, so that there is less and less carbon-14 in a dead body. The rate at which carbon-14 decays is constant and follows first order kinetics. It has a half-life of nearly 6000 years, so by measuring the relative amount of carbon-14 in a bone, archeologists can calculate when the person died. All living organisms consume carbon, so carbon dating can be used to date any living organism, and any object made from a living organism. Bones, wood, leather, and even paper can be accurately dated, as long as they first existed within the last 60,000 years. This is all because of the fact that nuclear reactions naturally occur in living organisms.

Which are the two most common radioactive decays happening in human body?


Which of the following is non-metallic?


Which of the following statements is not correct?


The spin magnetic moment of cobalt in the compound Hg [Co(SCN)4] is:-


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How is the variability in oxidation states of transition metals different from that of p-block elements?


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The trend of which property is represented by the following graph?


Account for the following:

Zirconium (Zr) and Hafnium (Hf) are difficult to separate.


Compare the general characteristics of the first series of the transition metals with those of the second and third series metals in the respective vertical columns. Give special emphasis on the following point:

Ionisation enthalpies


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