Description : (a) Write electron dot diagram for chlorine (At No. 17) and calcium (At No. 20). Show the formation of calcium chloride by transfer of electrons. (b) Identify the nature of above compound’and explain three physical properties of such compound. -Chemistry
Last Answer : (b) It is ionic compound. Physical properties 1.It is hard and solid. 2.It has high melting and boiling point. 3.It soluble in water.
Description : Which one of the following statements concerning elements in the Periodic Table is correct? A Elements of the same group all have the same number of electrons in the outermost occupied electron shell. B ... (Group 17) are all gases at room temperature. E The Group 13 elements are all metals.
Last Answer : D) Are compounds that exhibit both metallic & non-metallic properties to some extent and are exemplified by elements like germanium, silicon & boron
Description : (a) Show on a diagram the transfer of electrons between the atoms in the formation of MgO. Write symbols of cation and anion present in MgO. (b) Name the solvent in which ionic compounds are generally soluble. (c) Why are aqueous solutions of ionic compounds able to conduct electricity? -Chemistry
Last Answer : (b) Ionic compounds are soluble in water. (c) It is because aqueous solutions consist of ions which can move freely in them and carry current.
Description : (a) Show the formation of Na2O by the transfer of electrons between the combining atoms. (b) Why are ionic compounds usually hard? (c) How is it that ionic compounds in the solid state do not conduct electricity but they do so when in molten state? -Chemistry
Last Answer : (b) It is due to strong force of attraction between oppositely charged ions. (c) In solid state, ions are not free to move whereas in molten state ions are free to move, therefore, they conduct electricity in molten state.
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.
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.
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.
Description : Identify the type of reaction(s) in the following equations. (i)CH4 + 2O2 CO2 + 2 H2O (ii) Pb(NO3)2 + 2KI ——–>Pbl2 + 2KNOs (iii) CaO + H2O ——–> Ca(OH)2 (iv) CuSO4 + Zn ——–> ZnSO4 + Cu -Chemistry
Last Answer : Answer. (i) Combustion reaction and oxidation reaction. (ii)Double displacement reaction and precipitation reaction. (iii) Combination reaction. (iv) Displacement reaction.
Description : Which of the following is an acidic constituent of B.F. slag? (A) SiO2 (B) FeO (C) MgO (D) CaO
Last Answer : Option A
Description : How many dots would be used for the electron-dot structure of sr?
Last Answer : Need answer
Description : (3) preventing rapid setting of cement Explanation: Portland cement clinker is a hydraulic material which shall consist of at least two-thirds by mass of calcium silicates, the remainder consisting of ... mixed with water by way of a complex series of chemical reactions still only partly understood.
Last Answer : Milk is a colloidal system in which: (1) Water is dispersed in fat (2) Fat is dispersed in water (3) Fat and water are dispersed in each other (4) Fat is dissolved
Description : Calcium acetate on strong heating gives (a) Methane + CaCO3 (b) Ethane + CaCO3 (c) Acetone + CaCO3 (d) Ethane + CaO
Last Answer : Acetone + CaCO3
Description : What is the common name for calcium oxide, CaO?
Last Answer : ANSWER: QUICKLIME (LIME)
Description : Identify the alloy containing a non-metal as a constituent in it. (1) Bronze (2) Invar (3) Steel
Last Answer : Steel
Description : (a) State and explain Kohlrausch law. (b) How much electricity in terms of Faradays is required to produce 20 g of calcium from molten CaCl2? -Chemistry
Last Answer : a) Corrosion is an electrochemical phenomenon. At a particular spot of iron j oxidation it takes place and the spot behaves j as anode and the reaction will be: i At anode : 2Fe(s) → 2Fe2+ + 4e- Electrons ... Ca i.e. 40 g of Ca requires electricity = 2F ∴ 20 g of Ca will require electricity = 1F
Description : Oxygen differs from the other elements of the group. Compounds of oxygen with metals are more ionic in nature and hydrogen bonding is more important f
Last Answer : Oxygen differs from the other elements of the group. Compounds of oxygen with metals are more ionic in nature ... H_(2)O lt H_(2)Te -` boiling point
Last Answer : Oxygen differs from the other elements of the group. Compounds of oxygen with metals are more ... oxides are usually covalent and acidic in nature
Description : What is the percent composition of calcium (Ca) in (CaO)?
Last Answer : 40 g / 56 g X 100%
Description : What is the percent composition of calcium ca in cao?
Last Answer : 40g/56g x 100%= 71.43 % - APEX
Description : What is the ionic compound for calcium bromide?
Last Answer : The ionic compound calcium bromide is CaBr2.
Description : Nickel is a constituent of (A) Bronze (B) Solder (C) Duralumin (D) Monel metal
Last Answer : (D) Monel metal
Description : Low grade phosphate rock can be used in electrical furnace, because (A) Of the better CaO/SiO2 balance for slag formation (B) CaO content is less (C) It is cheap (D) It produces low cost product
Last Answer : (A) Of the better CaO/SiO2 balance for slag formation
Description : (4) less soluble in blood than nitrogen at high pressure Explanation: Deep-sea divers have their oxygen supply mixed with helium in order to avoid the toxic nature of oxygen under extreme pressures. The ... blood which blocks blood flow as the diver comes to the surface of the sea from underwater.
Last Answer : The chemical bahaviour of an atom depends upon - (1) the number of protons in its nucleus (2) the number of neutrons in the nucleus (3) the number of electrons orbiting around the nucleus (4) the number of nucleons in the nucleus
Description : Draw the atomic structure of (i) an atom with same number of sub-atomic particles, (ii) an atom with same number of electrons in L and M shell. -Chemistry 9th
Last Answer : (i) Oxygen Number of electrons = 8 Number of protons= 8 Number of neutron= 8 (ii) Argon Atomic number =18=2,8,8 No of electrons in L shell = 8 No of electrons in M shell = 8
Description : How do you know what compound should have ionic structure?
Last Answer : What is the answer ?
Description : Give reason for the following: (a) Aluminium oxide is considered as an amphoteric oxide. (b) Ionic compounds conduct electricity in molten state. -Chemistry
Last Answer : a) Aluminium oxide reacts with both acids as well as bases.b) Ionic compounds in molten state conduct electricity. Explanation: a) An amphoteric oxide as one that shows chemical reactivity with ... ions are present in the liquid state. These free ions enable the solution to conduct electricity.
Description : Organic chemistry involves molecules that contain which element? a. carbon c. oxygen b. nitrogen d. calcium
Last Answer : a. carbon
Description : Bronze medal is made up of metals ? A. copper,nickel B. copper, tin (Answer) C. copper, silver D. copper, zinc
Last Answer : B. copper, tin (Answer)
Description : From the elements: Cl, Br, F, O, Al, C, Li, Cs and Xe; choose the following: (a) The element with highest negative electron gain enthalpy. (b) The element with lowest ionization enthalpy. ( ... . (f)The element which belongs to zero group. (g) The elements which forms largest number of compounds.
Last Answer : Ans. (a). The element chlorine (Cl) has the highest negative electron gain enthalpy. (b). The element cesium (Cs) has lowest ionization enthalpy. (c). The element fluorine F has lowest atomic radius. (d ... zero group (or group 18). (g). The element carbon (C) forms the largest number of compounds.
Description : Explain the following : (i) Low spin octahedral complexes of nickel are not known. (ii) The π-complexes are known for transition elements only. (iii) CO is a stronger ligand than NTL, for many metals. -Chemistry
Last Answer : (i) The electronic configuration of Ni is [Ar] 3d8 4s2 which shows that it can only form two types of complexes i.e. square planar (dsp2) in presence of strong ligand and tetrahedral (sp3) in ... more splitting of d-orbitals and moreover it is also able to form π bond due to back bonding.
Description : Why do metals conduct electricity but crystals of ionic compounds do not conduct electricity ?
Last Answer : Metals have free electrons. These electrons, created to gain the electromagnetic positivity and octal structure of the metal, flow from the negative side of the electric source to the positive edge ... electrons does not occur in it. Therefore crystals of ionic compounds do not conduct electricity.
Description : Give reason .the compounds of alkaline earth metals are less ionic than alkali metals
Last Answer : Ans This is due to increased nuclear charge and smaller size.
Last Answer : This is due to increased nuclear charge and smaller size.
Description : Bonds formed by the sharing of an electron pair between two atoms are known as - (1) Covalent bonds (2) Ionic bonds (3) Weak bonds (4) None of the above
Last Answer : (1) Covalent bonds Explanation: Bonds which are formed by the sharing of an electron pair between two atoms are known as covalent bonds.
Description : In molecule of calcium sulfide calcium has two valence electron bonds and a sulfur atom has six valence electrons. How many lone pairs of electrons are present in the Lewis structure of calcium?
Description : What of the element out of calcium argon sodium nitrogen oxygen and chlorine can become stable by losing 1 electron?
Last Answer : Sodium. A sodium atom has one valence electron in its 3rd energy level. This is very unstable, so a sodium atom will lose that single valence electron to another atom (nonmetal), and the 2nd energy ... sodium ion, Na+, will bond with a negatively charged ion; either a nonmetal or a polyatomic ion.
Description : In an electron dot diagram of potassium There is one dot. In an electron dot diagram of silicon there are four dots. Which element would you expect to be more reactive?
Last Answer : silicon
Description : Explain why calcium metal after reacting with water starts floating on its * surface. Write the chemical equation for the reaction. Name one more metal that starts floating after some time when immersed in water. -Chemistry
Last Answer : Calcium starts floating because the bubbles of hydrogen gas formed stick to the surface of metal. Magnesium reacts with hot water and starts floating due to the bubbles of hydrogen gas sticking to its surface.
Description : Heavy water used in the nuclear reactors to slow down the speed of neutrons is (A) Highly purified water (B) A compound of oxygen and deuterium (C) Water having dissolved salts of heavy metals (D) None of these
Last Answer : (B) A compound of oxygen and deuterium
Description : You are given samples of three metals. Sodium, magnesium and copper. Suggest any two activities to arrange them in order of decreasing activity. -Chemistry
Last Answer : Activity 1: Sodium reacts with cold water vigorously to form sodium hydroxide and hydrogen gas Magnesium does not react with cold water but with hot water to form magnesium ! hydroxide and hydrogen gas. Hence sodium is more reactive than magnesium.
Description : Compare the following complexes with respect to their shape, magnetic behaviour and the hybrid orbitals involved : (i) [CoF4]2- (ii) [Cr(H2O)2(C2O4)2]– (iii) [Ni(CO)4] (Atomic number : Co = 27, Cr = 24, Ni = 28) -Chemistry
Last Answer : (i) [COF4]2_ : Tetrafluorido cobalt (III) ion Coordination number = 4 Shape = Tetrahedral Hybridisation = sp3 Important Questions for Class 12 Chemistry Chapter 9 Coordination Compounds Class 12 Important Questions 7
Description : What is the primary CONSTITUENT of human bones? w) Calcium sulfate x) Calcium carbonate y) Hydroxyapatite (pron: high-drox-ee-ap-eh-tite) z) Chloroapatite (pron: klor-o-ap-eh-tite)
Last Answer : ANSWER: Y -- HYDROXYAPATITE
Description : What is the primary constituent of marble? w) Calcium carbonate x) Calcium sulfate y) Hydroxyapatite z) Chloroapatite
Last Answer : ANSWER: W -- CALCIUM CARBONATE
Description : The 1936 Nobel Prize in chemistry was awarded to Peter J.W. Debye for his studies of: w) kinetic energy of colliding particles x) electron configuration y) dipole moments z) conformations of cyclohexane
Last Answer : ANSWER: Y -- DIPOLE MOMENTS
Description : There are two elements calcium (atomic number 20) and argon (atomic number 18) The mass number of both the elements is 40. They are therefore known as (a) isotones (b) isochores (c) isobars (d) isotopes
Last Answer : Ans:(c)
Description : Which raw material is used to impart colour to the glass? a) Al2O3 b) CoO c) CaO d) MgO
Last Answer : b) CoO
Description : Which one of the following is classified as a covalent network solid crystal? w) CaO x) SiO2 y) CO2 z) Pb
Last Answer : ANSWER: B -- SiO2
Description : Mark the compound which possesses ionic, covalent and coordinate bonds. (1) NH4C1 (2) SO3 (3) SO2 (4) H2O
Last Answer : (1) NH4C1 Explanation: Ammonium chloride (NH4Cl) is generally considered as an ionic compound but this compound has three different types of bond.