Give reason for the colour imparted to the flame by alkali metals

Give reason for the colour imparted to the flame by alkali metals 
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Answer :

The alkali metals and their salts impart characteristic colour to an oxidizing flame. This is because the heat from the flame excites the outermost orbital electron to a higher energy level. When the excited electron comes back to the ground state, there is emission of radiation in the visible region. 
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Colour imparted to the Bunsen flame by strontium salt is - (1) bluish green (2) apple-green (3) brick red (4) crimson red

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Last Answer : (4) crimson red Explanation: A flame test is performed by introducing a sample into the blue flame of a bunsen burner and noting any change in the colour of the flame. The tests can be used ... metallic elements in salts. With strontium salt, the colour of Bunsen flame ranges from crimson to red.

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Description : What is the colour imparted to the flame by Ca,Sr and Ba?

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Description : why alkali metals impart color to the flame?

Last Answer : Ans. Alkali metals have low ionization enththalpies. Their valence electrons get excited by absorbing energy from the flame. When these electrons return to the ground state, the energy is emitted In the form of light.

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Give reason .the compounds of alkaline earth metals are less ionic than alkali metals

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Last Answer : Ans This is due to increased nuclear charge and smaller size.

Give reason for the following: (i)alkali metals do not occur free in nature. (ii)alkali metals have low I .E. (iii)LiI is more soluble than KI in ethanol.

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Give reason .the melting point and boiling point of alkali metals are low

Description : Give reason .the melting point and boiling point of alkali metals are low 

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Give reason .the compounds of alkaline earth metals are less ionic than alkali metals

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Give reason for the higher melting point and boiling point of alkali earth metals than alkali metals.

Description : Give reason for the higher melting point and boiling point of alkali earth metals than alkali metals. 

Last Answer : The melting and boiling points of these metals are higher than the corresponding alkali metals due to smaller sizes. 

Give reason for the appearance of colour in alkali metal halides.

Description : Give reason for the appearance of colour in alkali metal halides. 

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Description : What is the reason for the increasing stability of peroxide & superoxide of alkali metals down the group? 

Last Answer : On combustion in excess of air, lithium forms mainly the oxide, Li2O (plus some peroxide Li2O2), sodium forms the peroxide, Na2O2 (and some superoxide NaO2) whilst potassium, rubidium and ... are also paramagnetic. Sodium peroxide is widely used as an oxidising agent in inorganic chemistry.  

How many of following metals impart a characteristic colour to the Bunsen flame ? `(i) Na " " (ii) Li " " (iii) K " " (iv) Ba` `(v) Sr " " (vi) Mg " "

Description : How many of following metals impart a characteristic colour to the Bunsen flame ? `(i) Na " " (ii) Li " " (iii) K " " (iv) Ba` `(v) Sr " " (vi) Mg " "

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Description : Do all metals produce colour in a flame?

Last Answer : Need answer

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Description : Give reason: Glass objects when held to flame acquires golden yellow colour.

Last Answer : The sodium content of sodium silicate present in glass makes the flame to acquire golden yellow colour to the flame.

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Description : Blue colour is imparted to glass by the addition of (A) FeSO4 (B) PbO (C) CaO (D) NaOH

Last Answer : (C) CaO

Why do the the alkali metals give blue solution ,when treated with liq NH3?

Description : Why do the the alkali metals give blue solution ,when treated with liq NH3? 

Last Answer : The alkali metals dissolve in liquid ammonia giving deep blue solutions which are conducting in nature. The blue colour of the solution is due to the ammoniated electron which absorbs ... ammonia.) In concentrated solution, the blue colour changes to bronze colour and becomes diamagnetic.  

Give the names of four alkali metals:

Description : Give the names of four alkali metals: 

Last Answer : ANSWER: LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CESIUM, AND FRANCIUM  

What are the alkali metals ?

Description : What are the alkali metals ?

Last Answer : The remaining 6 elements of hydrogen in group 1 of the periodic table .

How does the of Hydration Enthalpy of alkaline earth metals vary & compare it with alkali metals

Description : How does the of Hydration Enthalpy of alkaline earth metals vary & compare it with alkali metals

Last Answer : Ans The hydration enthalpies of alkaline earth metal ions decrease with increase in ionic size down the group. Be2+> Mg2+ > Ca2+ > Sr2+ > Ba2+ The hydration enthalpies of alkaline earth metal ions ... MgCl2 and CaCl2 exist as MgCl2.6H2O and CaCl2· 6H2O while NaCl and KCl do not form such hydrates.

How does the of Ionization Enthalpy of alkaline earth metals vary in comparison to alkali metals

Description : How does the of Ionization Enthalpy of alkaline earth metals vary in comparison to alkali metals

Last Answer : Ans The alkaline earth metals have low ionization enthalpies due to fairly large size of the atoms. Since the atomic size increases down the group, their ionization enthalpy decreases The first ... enthalpies of the alkaline earth metals are smaller than those of the corresponding alkali metals.

How does the atomic and Ionic Radii of alkaline earth metals vary in comparison to alkali metals

Description : How does the atomic and Ionic Radii of alkaline earth metals vary in comparison to alkali metals

Last Answer : Ans The atomic and ionic radii of the alkaline earth metals are smaller than those of the corresponding alkali metals in the same periods. This is due to the increased nuclear charge in these elements. Within the group, the atomic and ionic radii increase with increase in atomic number.

State as to why: (a) A solution of Na2CO3 is alkaline? (b)alkali metals are prepared by electrolysis of their fused chlorides ? (c)sodium is found to be more useful than potassium ?

Description : State as to why: (a) A solution of Na2CO3 is alkaline? (b)alkali metals are prepared by electrolysis of their fused chlorides ? (c)sodium is found to be more useful than potassium ?

Last Answer : Ans. (a) It undergoes hydrolysis to produce a strong base NaOH . (b) When the aq. Solution of any alkali metal is subjected to electrolysis ,H2 instead of the alkali metal is produced at the ... of sugars and amino acids into the cells. Thus, sodium is found to be more useful than potassium.

what are the common physical features of alkali metals?

Description : what are the common physical features of alkali metals?

Last Answer : Ans. Large Atomic and ionic radii, Low ionization enthalpies, metallic character, low melting and boiling Point, form ionic bond, low density,show flame coloration ,photoelectric effect.

what do you understand by “Non stoichiometric hydrides”? Do you think this type of hydrides to be formed by alkali metals? Justify your answer.

Description : what do you understand by “Non stoichiometric hydrides”? Do you think this type of hydrides to be formed by alkali metals? Justify your answer.

Last Answer : Ans: Hydrides which are deficient in hydrogen and in which the ratio of hydrogen to metal is fractional are called non-stoichiometric hydrides. This type of hydrides are formed by d-and ... they form only stoichiometric hydrides. In other words alkali metals do not form non-stoichiometric hydrides.

Which one of the alkali metals, forms only, the normal oxide, M2O on heating in air (1) Na (2) Rb (3) K (4) Li

Description : Which one of the alkali metals, forms only, the normal oxide, M2O on heating in air (1) Na (2) Rb (3) K (4) Li

Last Answer : Li

Mention the Points of Difference between ‘Lithium and other Alkali Metals’

Description : Mention the Points of Difference between ‘Lithium and other Alkali Metals’

Last Answer : (i) Lithium is much harder. Its m.p. and b.p. are higher than the other alkali metals. (ii) Lithium is least reactive but the strongest reducing agent among all the alkali metals. ... and Li2O are comparatively much less soluble in water than the corresponding compounds of other alkali metals. 

Explain the stability of carbonates & bicarbonates of alkali metals .

Description : Explain the stability of carbonates & bicarbonates of alkali metals . 

Last Answer : The alkali metals form salts with all the oxo-acids. They are generally soluble in water and thermally stable. Their carbonates (M2CO3) and in most cases the hydrogencarbonates (MHCO3) also are highly ... the formation of more stable Li2O and CO2. Its hydrogencarbonate does not exist as a solid.  

What are the uses of alkali metals ?

Description : What are the uses of alkali metals ? 

Last Answer : Lithium metal is used to make useful alloys, for example with lead to make white metal' bearings for motor engines, with aluminium to make aircraft parts, and with magnesium to make armour ... also used as an excellent absorbent of carbon dioxide. Caesium is used in devising photoelectric cells. 

How does alkali metals react with halogens?

Description : How does alkali metals react with halogens?  

Last Answer : The alkali metals readily react vigorously with halogens to form ionic halides, M+X-. However, lithium halides are somewhat covalent. It is because of the high polarisation capability of lithium ion ( ... size can be easily distorted, among halides, lithium iodide is the most covalent in nature. 

Explain the reactivity of alkali metals towards water.

Description : Explain the reactivity of alkali metals towards water. 

Last Answer : The alkali metals react with water to form hydroxide and dihydrogen. It may be noted that although lithium has most negative E0 value, its reaction with water is less vigorous than ... explosively with water. They also react with proton donors such as alcohol, gaseous ammonia and alkynes.  

How does the of Hydration Enthalpy of alkaline earth metals vary & compare it with alkali metals

Description : How does the of Hydration Enthalpy of alkaline earth metals vary & compare it with alkali metals  

Last Answer : The hydration enthalpies of alkaline earth metal ions decrease with increase in ionic size down the group. Be2+> Mg2+ > Ca2+ > Sr2+ > Ba2+ The hydration enthalpies of alkaline earth metal ... and CaCl2 exist as MgCl2.6H2O and CaCl2· 6H2O while NaCl and KCl do not form such hydrates.  

How does the of Ionization Enthalpy of alkaline earth metals vary in comparison to alkali metals

Description : How does the of Ionization Enthalpy of alkaline earth metals vary in comparison to alkali metals 

Last Answer : The alkaline earth metals have low ionization enthalpies due to fairly large size of the atoms. Since the atomic size increases down the group, their ionization enthalpy decreases The first ionisation ... of the alkaline earth metals are smaller than those of the corresponding alkali metals.  

How does the atomic and Ionic Radii of alkaline earth metals vary in comparison to alkali metals

Description : How does the atomic and Ionic Radii of alkaline earth metals vary in comparison to alkali metals 

Last Answer : The atomic and ionic radii of the alkaline earth metals are smaller than those of the corresponding alkali metals in the same periods. This is due to the increased nuclear charge in these elements. Within the group, the atomic and ionic radii increase with increase in atomic number.

What happens when alkali metals react with dihydrogen?

Description : What happens when alkali metals react with dihydrogen? 

Last Answer : The alkali metals react with dihydrogen at about 673K (lithium at 1073K) to form hydrides. All the alkali metal hydrides are ionic solids with high melting points. 

How the atomic and ionic radii varies in alkali metals

Description : How the atomic and ionic radii varies in alkali metals 

Last Answer : The atomic and ionic radii of alkali metals increase on moving down the group i.e., they increase in size while going from Li to Cs.

Why alkali metals are highly electro positive & they are not found in free state ?

Description : Why alkali metals are highly electro positive & they are not found in free state ?

Last Answer : The loosely held s-electron in the outermost valence shell of these elements makes them the most electropositive metals. They readily lose electron to give monovalent M+ ions. Hence they are never found in free state in nature. 

Name the gas liberated when alkali metals react with dil acid?

Description : Name the gas liberated when alkali metals react with dil acid?  

Last Answer : The alkaline earth metals readily react with acids liberating dihydrogen gas . M + 2HCl →→MCl2 + H2

How the ionization enthalpy varies in alkali metals

Description : How the ionization enthalpy varies in alkali metals 

Last Answer : Ionization enthalpy decrease down the group from Li to Cs. 

Why I group elements are called alkali metals ?

Description : Why I group elements are called alkali metals ? 

Last Answer : These are called so because they form hydroxides on reaction with water which are strongly alkaline in nature. 

Name any four alkali metals.

Description : Name any four alkali metals.

Last Answer : ANSWER: LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CESIUM, AND FRANCIUM

The elements in group 1A of the periodic table are called: w) halogens x) alkaline earths y) alkali metals z) rare earths

Description : The elements in group 1A of the periodic table are called: w) halogens x) alkaline earths y) alkali metals z) rare earths

Last Answer : ANSWER: Y -- ALKALI METALS

Which of the following alkali metals has highest specific heat? (1) Caesium (2) Rubidium (3) Potassium (4) Lithium

Description : Which of the following alkali metals has highest specific heat? (1) Caesium (2) Rubidium (3) Potassium (4) Lithium

Last Answer : Lithium

Give reasons : a. Alkali metals have low ionization energies.  b. Inert gases have exceptionally high ionization energies.

Description : Give reasons : a. Alkali metals have low ionization energies.  b. Inert gases have exceptionally high ionization energies.

Last Answer : Give reasons : a. Alkali metals have low ionization energies. b. Inert gases have ... d. Noble gases possess relatively large atomic size.

Metals which do not give flame test ?

Description : Metals which do not give flame test ?

Last Answer : Metals which do not give flame test ? A. Be B. Li C. Mg D. Ba

Why Be and Mg do not impart colour to the flame ?

Description : Why Be and Mg do not impart colour to the flame ?

Last Answer : Ans : The electrons in beryllium and magnesium are too strongly bound to get excited by flame. Hence, these elements do not impart any colour to the flame.

Why Be and Mg do not impart colour to the flame ?

Description : Why Be and Mg do not impart colour to the flame ? 

Last Answer : The electrons in beryllium and magnesium are too strongly bound to get excited by flame. Hence, these elements do not impart any colour to the flame. 

What is the oxidation number of alkali metals ?

Description : What is the oxidation number of alkali metals ?

Last Answer : Oxidation number of alkali metals + 1.

For alkali metals, which one of the following trends is incorrect ?

Description : For alkali metals, which one of the following trends is incorrect ?

Last Answer : For alkali metals, which one of the following trends is incorrect ? A. Hydration energy `: Li^(+) gt Na^(+) ... D. Atomic size `: Li lt Na lt K lt Rb`