Give reason: a) Metals are electropositive. b) Non-metals are electronegative. c) Even though hydrogen is a non-metal, it is electropositive. d) Sodium is electropositive.

1 Answer

Answer :

a) Metals are electropositive. Electropositive element has the tendency to lose electrons and form cation.Metals are electron donors. Hence they are electropositive.
b) Non-metals are electronegative. Electronegative element has the tendency to gain electrons and form anions. Non-metals are electron acceptors. Hence they are electronegative.
c) Even though hydrogen is a non-metal, it is electropositive. At low temperatures hydrogen shows metallic properties.
d) Sodium is electropositive. Sodium is electropositive because donates electrons from last orbit to another element and becomes electropositive.

Related questions

Description : Give reason: Metals belonging to the same group form good alloys.

Last Answer : As metals belonging to the same group in the periodic table have similarities in electronic configuration.

Description : Give reason: Some metals are more reactive than others.

Last Answer : Metals are electropositive and have tendency to donate electrons. Some elements give up their valence electrons and hence more reactive.

Description : Name some metals which do not displace hydrogen from dilute acids.

Last Answer : Platinum, gold, silver, mercury & copper do not displace hydrogen from dilute acids.

Description : How do metals react with hydrogen?

Last Answer : Metals react with hydrogen to form respective hydrides. Calcium reacts with hydrogen to form calcium hydride.

Description : Sodium displaces hydrogen from dilute acids violently but copper does not displace hydrogen from dilute acids. Why?

Last Answer : Sodium is highly reactive than copper. Hence reaction with sodium reacts violently then that of copper.

Description : Petrol is not selected for preserving sodium or potassium metal. Why?

Last Answer : Petrol evaporates easily and is costly hence kerosene is used.

Description : Metals, Metalloids and Non-metals

Last Answer : The elements in the periodic table can also be divided according to whether they are metals, metalloids or non-metals. The zigzag line separates all the elements that are metals from those that ... more metals then non-metals. Metals, metalloids and non-metals all have their own specific properties.

Description : Give reason: Even though silicon is a non-metal it resembles metals in its properties.

Last Answer : When red hot silicon reacts with steam, it liberates hydrogen. Even when metals like hot iron, zinc or magnesium react with steam, they liberate hydrogen with their respective metal oxides. Hence silicon resembles metals in some properties.

Description : science Topic : Metals Fill in the blanks.

Last Answer : 1. An example of a liquid metal is Mercury/gallium. 2. A metal which is soft is sodium. 3. A metal which lacks ductility is sodium. 4. A non-metal which is lustrous is graphite/iodine ... 59. Aluminium+ copper+ magnesium+ manganese is useful in making aircraft bodies. 60. Ornamental gold is an alloy

Description : How are the properties of alloys different from those of metals?

Last Answer : Copper is reddish and zinc is grayish in colour where as brass which is an alloy of copper and zinc is golden yellow in colour. Iron is a magnetic substance but stainless steel, an alloy of iron is non magnetic.

Description : How do metals react with sulphur?

Last Answer : Metals react with sulphur forming respective sulphides. Iron reacts with sulphur forming ferrous sulphide.

Description : How do metals react with chlorine?

Last Answer : Metals react with chlorine to form respective chlorides. Aluminium reacts with chlorine to form aluminium chloride.

Description : How do metals react with nitrogen?

Last Answer : Metals react with nitrogen forming respective nitrides at high temperature. Magnesium reacts with nitrogen to form magnesium nitride.

Description : Metals

Last Answer : Examples of metals include copper (Cu), zinc (Zn), gold (Au), silver (Ag), tin (Sn) and lead (Pb). The following are some of the properties of metals: Thermal conductors Metals ... are nonmagnetic. You can see how the properties of metals make them very useful in certain applications.

Description : Describe the effects of temperature on conductivity of metals.

Last Answer : For metallic conductors, the resistance of all pure materials increases linearly with temperature over a limited range of temperature hence conductivity decreases. For metallic conductors, ... vibrating ions collide with the moving electrons. Hence resistance increases with increasing temperature.

Description : With rise in temperature the resistance of pure metals?

Last Answer : With rise in temperature the resistance of pure metals increases.

Description : Give reason: Gold occurs in native form.

Last Answer : Gold is low in the reactivity series. It is least reactive or unreactive. Hence gold is found in free state.

Description : Give reason: Iron displaces copper from copper sulphate solution.

Last Answer : Iron is more reactive than copper. Hence it displaces copper from copper sulphate solution.

Description : Give reason: Aluminium / Iron become passive when immersed in concentrated nitric acid.

Last Answer : Since concentrated nitric acid is a powerful oxidising agent, it forms a protective oxide layer on the metal instantly

Description : Give reason: a) Magnesium reacts more vigorously with hydrochloric acid than zinc or copper. b) Iron takes more time to react with dilute hydrochloric acid than magnesium and zinc

Last Answer : a) Magnesium reacts more vigorously with hydrochloric acid than zinc or copper. The reactivity of magnesium is higher than that of zinc. Hence it reacts with hydrochloric acid more vigorously. b) ... acid than magnesium and zinc As iron has lowest reactivity when compare to magnesium and zinc.

Description : Give reason: Magnesium ribbon should not be kept near bottles containing volatile chemicals.

Last Answer : Magnesium is a reactive metal therefore it should not be kept near bottles containing volatile chemicals.

Description : Give reason: During burning of magnesium not only magnesium oxide is formed but also magnesium nitride is formed.

Last Answer : Due to high temperature the triple bond between nitrogen atoms is broken and a small quantity of magnesium nitride is formed.

Description : Give reason: Metallic articles which are exposed to air over long period of time lose their lustre.

Last Answer : Due to the formation of oxide, hydroxide and carbonate layers.

Description : Give reason: a) Iron exposed to air rusts quickly during rainy season.

Last Answer : a) Iron exposed to air rusts quickly during rainy season. Due to the presence of excess water vapour. b) Iron nail kept in a closed jar containing calcium chloride does not rust. As air is dry ... ) Tin is used to coat the inner walls of brass and copper utensils. To avoid corrosion or rusting.

Description : Why is sodium preserved in kerosene?

Last Answer : Sodium is highly reactive in air. It reacts with air gradually forming sodium carbonate. It catches fire and burns when exposed to air. It does not react with kerosene so sodium is preserved in kerosene.

Description : Briefly explain the Lane process of manufacture of hydrogen.

Last Answer : In a hard glass borosilicate tube with both sides open, take 5g of iron filings in a horizontal position and arrange the apparatus as shown in the figure. When water is boiled in ... which passes through the horizontal tube containing iron filings. Iron filings react with steam forming hydrogen.

Description : Why do gold ornaments look new even after several years of use?

Last Answer : Gold does not corrode when exposed to atmosphere. It is a highly unreactive metal and is unaffected by air, water vapour and other gases in atmosphere.

Description : Which metal is present both in brass and bronze?

Last Answer : Copper

Description : Explain the process of zone refining. Name one metal refined by this method.

Last Answer : The apparatus used for zone refining consists of a circular heater fitted around the rod of impure metal at one end. The circular heater is slowly moved to the other end. At the heated zone, ... in solid metal passes into the adjacent molten part. A metal refined by zone refining is germanium.

Description : Mention the methods of obtaining ultra pure metal.

Last Answer : a) Fractional crystallization or zone refining. b) Vacuum melting c) Distillation d) Chemical vapour deposition e) Liquation process

Description : Which gas is always produced if a metal reacts with water or dilute acid?

Last Answer : Hydrogen

Description : In a solution of silver nitrate, a copper plate was dipped. After some time, silver from the solution was deposited on the copper plate. Which metal is more reactive – copper or silver?

Last Answer : More reactive metal displaces a less reactive metal. Hence copper metal is more reactive.

Description : Assertion : Hydrometallurgy involves dissolving the ore in a suitable reagent followed by precipitation by a more electropositive metal. Reason : Copp

Last Answer : Assertion : Hydrometallurgy involves dissolving the ore in a suitable reagent followed by precipitation ... : Copper is extracted by hydrometallurgy.

Description : Highly electropositive metals can not be extracted by carbon reduction process because these :

Last Answer : Highly electropositive metals can not be extracted by carbon reduction process because these : A. Metals ... D. Loss of metal is more by vaporisation

Description : How the most electropositive metals are isolated from their ores ?

Last Answer : Ans. The most electropositive metals are isolated from their ores by electrolysis of fused ionic salts.

Description : What are memory alloys? How are they useful?

Last Answer : Certain alloys which regain their original shape when deformed are called memory alloys. Preparation of memory alloys saves energy of melting and recasting of used articles.

Description : Write a note on contributions of Indians to metallurgy.

Last Answer : a) Romans used armour and cutlery made from Indian iron. b) Indian metallurgist Nagarjuna wrote the book Rasaratnakara' in 9th century BC which explained the preparation of various metallic ... near Qutab Minar constructed by Vikramadithya about 1600 years ago has withstood the action of weather.

Description : Why is 6% to 8% copper added to gold in making ornaments?

Last Answer : Pure gold is very soft, it cannot be used to make artistic ornaments. To make it hard, improve the looks and colour, 6 to8% copper is added to ornamental gold.

Description : What property of invar steel is used in making pendulums and measuring tapes?

Last Answer : Invar steel has the least co-efficient of linear expansion.

Description : What property of stainless steel is used in making surgical instruments?

Last Answer : Surgical steel is not attacked by mild chemicals easily and it does not corrode.

Description : Why are alloys made?

Last Answer : Alloys give desired properties to the metal. It improves the properties of metals.

Description : How is an alloy formed?

Last Answer : Alloysare prepared by mixing the various metals in their molten state and cool them to room temperature. Better quality can be made by mixing metals using ultrasonics.

Description : What is an alloy?

Last Answer : An alloy is a homogenous mixture of two or more metals or metal with a non-metal. Example: Brass is an alloy of two metals copper and zinc. Steel is an alloy of a metal iron and non-metal carbon.

Description : Briefly explain the electrolytic refining of copper.

Last Answer : Copper is purified by electrolytic refining. The apparatus consists of an electrolytic tank containing copper sulphate solution as electrolyte. A set of thick blocks of impure copper is made anode ... anode becomes thinner and pure cathode becomes thicker. The impurities collect at the bottom.

Description : What is electrolytic refining?

Last Answer : Electrolytic refining is a technique of ultra refining of metal. In this method, impure metal is taken as anode and pure metal are taken as cathode. Electric current is passed through the electrolyte to obtain pure metal at the cathode.

Description : What is meant by zone refining or fractional crystallization?

Last Answer : Zone refining is a technique of obtaining ultra pure metal. It is based on the principle of differences in solubility of impurities in liquid and solid states of the metal.

Description : What is meant by liquation process?

Last Answer : Liquation is a process of obtaining ultra pure metal. It is based on the principle that metals are readily fusible where as the impurities are infusible at the temperature at which the metals fuse.

Description : Name the process by which the refining of aluminium is done. Name the material used for the process.

Last Answer : Aluminium is refined by electrolytic refining. Carbon lining acts as the cathode and the graphite rods act as anode.

Description : Briefly explain the extraction of aluminium from alumina with chemical equations.

Last Answer : Aluminium oxide dissolved in molten cryolite is taken in a chamber with gently sloped base.The inner wall is made of carbon lining. Graphite rods are introduced in the electrolyte bath. The carbon lining ... is passed. Molten aluminium collects at the lining and flows out of the gently sloped base.

Description : What is cryolite? Write its chemical formula.

Last Answer : Cryolite is chemically sodium aluminium fluoride. Its molecular formula is Na3AlF6.