8881 + Interview Questions in Chemistry in Class 10 Page 158 InterviewSolution

7851.	An element has its electronic configuration as 2, 8, 2. Now anwswer the following questions : What is the group of this element?
Answer» Solution :Atomic number of element is 12 and its electronic CONFIGURATION is (2, 8, 2) . As it has 2 valence electrons, this element belongs to GROUP 2 and its name is MAGNESIUM (Mg).

Discussion

7852.	An element has its electronic configuration as 2, 8, 2. Now anwswer the following questions : What is the atomic number of this element ?
Answer» SOLUTION :ELECTRONIC configuration of this element is (2, 8, 2) `:.` The atomic number of this element is 12.

Discussion

7853.	An element has its electronic configuration as 2, 8, 2. Now anwswer the following questions : To which period does this element belong?
Answer» SOLUTION :Atomic NUMBER of this element is 12 and its ELECTRONIC configuration is (2, 8, 2) . It has 3 shells. The number of shells INDICATES the period number. Hence it belongs to period 3.

Discussion

7854.	An element has electronic configuration 2,8,4. It will be classified as
Answer» METAL non metal METALLOID NONE of these Answer :B

Discussion

7855.	An element has electrons configuration 2,8,4. It belong to which group and period of the Periodic Table
Answer» 2,4 14,3 14,4 3,14 Solution :The element has three shells, belongs to THIRD PERIOD. It has valence ELECTRONS and belongs to group 14.

Discussion

7856.	An element has atomic number 3. To which period of the periodic table does it belong?
Answer» SOLUTION :SECOND PERIOD.

Discussion

7857.	An element has atomic no. 16 It will belong to which period of the periodic table ?
Answer» 2 3 4 5 Solution :Z = 16, its ELECTRONIC configuration is 2,8,6. It BELONGS to THIRD period of the PERIODIC table as the last electron is present in the third shell.

Discussion

7858.	An element has atomic mass 93 g mol^(_1) and density 11.5 g cm^(-3). If the edge length of its unit cell is 300 pm, identify the type of unit cell.
Answer» BODY -CENTRED CUBIC UNIT cell face -centred cubic unit cell simple cubic None Answer :A

Discussion

7859.	Atomic number of element Z is 16. Is Z a metal or a non metal.
Answer» SOLUTION :NONMETAL

Discussion

7860.	An element has 12 neutrons in its nucleus. To which group of the periodic table it will belong?
Answer» 1 2 6 Impossible to predict Solution :The group NUMBER is decided by the NUMBEROF ELECTRONS is the valence shell. This depends on the atomic number .

Discussion

7861.	An element forms an oxide A_2O_3which is acidic in nature. Identify A as a metal or non-metal.
Answer» SOLUTION :Non-metal.

Discussion

7862.	An element common to all acid is
Answer» Chlorine Nitrogen Oxygen Hydrogen Answer :D

Discussion

7863.	An element combines with oxygen to give a compound with a high melting point. The compound is also soluble in water. The element is likely to be
Answer» CALCIUM CARBON silicon iron SOLUTION :calcium

Discussion

7864.	An element combines with oxygen to form an oxide. This oxide dissolves in water. This aqueous solution changes blue litmus to red. Write the nature of the element (metal or nonmetal)
Answer» SOLUTION :NONMETAL

Discussion

7865.	An element burns in oxygen to form its oxide which is soluble in water. This aqueous solution gives a pink colour with phenolphthalein. What conclusions do you draw from these observations?
Answer» SOLUTION :Element is a REACTIVE metal, its OXIDE has basic nature

Discussion

7866.	An element belongs to group 17 and period 3 of the periodic table. Write the following:Its metallic and nonmetallic nature
Answer» SOLUTION :NONMETALLIC

Discussion

7867.	An element becomes another element if the number of
Answer» PROTONS changes neutrons changes ELECTRONS changes Protons, neutrons, and electrons does not change Solution :a] Reason: The number of protons is the characteristic PROPERTY of an element and ALWAYS remains FIXED.

Discussion

7868.	An element B belongs to the second period and Group 13. Give the formula of the oxide.
Answer» SOLUTION :FORMULA of the OXIDE is `B_2 O_3`.

Discussion

7869.	An element A reacts with oxygen to form A2O. i] State the number of electrons in the outermost orbit of A. ii] To which group of the periodic table does A belong? iii] State whether A is a metal or a non-metal.
Answer» Solution :i] Given that element A reacts with oxygen to FORM AO it means that two atoms of A REACT with one atom of oxygen and hence, A has a valency of I. ii] It BELONGS to the first group of the periodic table SINCE it has a valency of I. III] A is a metal.

Discussion

7870.	An element A reacts with oxygen to form A_2 O. (i) State the number of electrons in the outermost orbit of A. (ii) To which group of the periodic table does A belong? (iii) State whether A is a metal or a non-metal.
Answer» Solution :(i) As the valency of oxygen is 2, the valency of A must be 1 in ORDER to obtain the compound `A_2 O` . Therefore, the number of ELECTRONS in the outermost orbit of A is 1. (ii) A BELONGS to Group 1 of the PERIODIC Table. Elements of this group have 1 ELECTRON in the outermost orbit. (iii) A is a metal. Elements of Group 1 having 1 electron in the outermost orbit have a tendency to lose electrons.

Discussion

7871.	An element A reacts with water to form a compound B which is used in white washing. The compound B on heating forms an oxide C which on treatment with water gives back B. Identify A, B and C and give the reactions involved.
Answer» SOLUTION :A is calcium it reacts with WATER to form calcium hydroxide which is used in WHITE washing so B is `Ca(OH)_2`. `Ca(s)+2H_2O(l)to Ca(OH)_2(aq)_B+H_2(g)` On HEATING compound B, i.e., calcium hydroxide it forms calcium oxide i.e., C `Ca(OH)_2to^(Heat)CaO_c+H_2O`

Discussion

7872.	An element A forms two oxides AO and AO_2 . The oxide AO is neutral whereas the oxide AO_2is acidic in nature. Would you call element A a metal or a non-metal ?
Answer» SOLUTION :ELEMENT A is a non-metal.

Discussion

7873.	An element A burns with golden flame in air. It reacts with another element B, atomic number 17to give a product C. An aqueous solution of the product C on electrolysis gives a compound D and liberates hydrogen. Identify A, B, C and D. Also write down the equations for the reactions involved.
Answer» Solution : Since the element A burns with golden flame in AIR, it is sodium (Na) which has electronic configuration 2, 8, 1. The element B with atomic number 17 is CHLORINE which has electronic configuration 2, 8, 7. Na and Cl react to form NaCl which is an ionic compound. Aqueous solution of NaCl on electrolysis GIVES NAOH and Cl, gas. THUS D is NaOH. Reactions are given as under :

Discussion

7874.	An element A burns with golden flame in air. It reacts with another element B, atomic number 17 to give to product C. An aqueous solution of productC on electrolytes gives a compound D and liberates hydrogen, Identify A, B ,C and D Also write down the equation for the reactions involved.
Answer» SOLUTION :`A-Na, B-Cl_2,C-NaCl,D-NaOH` `2Na+Cl_2 to 2NaCl` `2NaCl (AQ)+2H_2O(L)to 2NAOH (aq)+Cl_2(G)+H_2(g)`

Discussion

7875.	An element ‘M’ has atomic number 11. a)Write its electronic configuration. b)State the group to which ‘M’ belongs c)is 'M' a metal or a non - metal ? d)Write the formula of its chloride.
Answer» Solution :(a)2, 8, 1 (B) Group 1 (c) ‘M’ is a metal (d) MCI is formula of its CHLORIDE.

Discussion

7876.	An electron is revolving in an orbit with a veloc- ity of 5.46xx107 cm s^(-1) . Calculate the wave length associated with the electron.
Answer» Solution :Radius `r_n=(0.529xxn^2)/ZrArr3.3` `(0.529xx25)/ZrArrZ=4` `therefore` Atomic number of X is 4 and atomic number of is 28. Electronic configuration of Y is `1s^22s^22p^63s^23p^64s^23d^8` and valenc electrons are `4s^2` electrons Electron : `1 RARR N= 4,1=0 m=0,s=-1/2` Electron `2 rarr n= 4,1=0,m=0,s=-1/2`

Discussion

7877.	An electron is present in a hydrogen atom in the ground state and another electron is present in a smgle electron species of beryllium. In both the species the distance between the nucleus and electren 18 same. Calculate the difference in their energies.
Answer» Solution : radius of hydrogen atom in `1^(st)` ORBIT ` = (kn^2)/Z=kn^2=k.1^2=k ` Let radius of `n^(th)`orbit of `Be^(+3)=k` `therefore k=(kn^2)/4, therefore n^2=4, therefore n=2` ln order to MAINTAIN the same DISTANCE, the electron has to be present in the `2^(nd)` orbit of `Be^(+3)`. Energy of the electron in the 1st orbit of hydrogen `= (-kz^2)/(n^2)=-k` Energy of the electron in the `2^(nd)` orbit of `Be^(+3)` `=-(kz^2)/(n^2)` `= -(kxx4xx4)/(2xx2)=-4k` `therefore`Difference in energy `=(4k-k)=3k` `=(3xx13.6)EV` =40.8eV

Discussion

7878.	An electronhas mass thatis very muchlessthanproton.
Answer» ANSWER :TRUE

Discussion

7879.	An electrolyte and a nonelectrolyte .
Answer» SOLUTION :(i) An electrolyte releases ions is solution , WHEREASA nonelectrolyte does not RELEASE ions . (ii) An electrolyte conducts ELECTRICITY in aqueous SOLUTIONS , but not a nonelectrolyte does not .

Discussion

7880.	An electric refrigerator rated 300 W is used for 8 hours a day. An electric iron box rated 750 Wis used for 2 hours a day. Calculate the cost of using these appliances for 30 days, if the cost of 1 kWh is Rs. 3/-
Answer» Solution :The TOTAL energy consumed by the refrigcrator in 30 days `=400xx8xx0= 96000 Wh - 96 kWh` The total energy consumed by the IRON box in 30 days `750xx2xx30 = 45000 Wh= 45 kWh` The total energy consumed by the refrigerator and iron box is `96kWh +45kWh-141 kWh` The surn of bill amount for 141 kWh at RATE of Rs. 3 pcr 1 kWh is `-141 xx 3 = Rs. 423`

Discussion

7881.	An electric refrigerator rated 400 W is used for 8 hours a day. An electric iron box rated 750 W is used for 2 hours a day. Calculate the cost of using these appliances for 30 days, if the cost of I kWh is Rs 3/-.
Answer» SOLUTION :The total energy consumed by the refrigerator in 30 days `=400 times 8 times 30=96000 Wh=96kWh` The total energy consumed by the iron BOX in 30 days `=750 times 2 times 30 =45000Wh=45kWh` The total energy consumed by the refrigerator and iron box is `=96kWh+45kWh=141kWh` The sum of bill amount for 141 kWh at rate of Rs. 3 per 1 kWh is `=141 times 3` = Rs. 423

Discussion

7882.	An electric motor is taken out from a toy ear. How do you convert this motor into a small electric generator? Compare the function of electric generator with the phenomenon of electromagnetic induction.
Answer» Solution :To convert an electric motor taken out from the toy car into a small electric generator we can follow these steps: Take the electric motor from the toy car out of the vehicle. Now connect some rotator cuff or anything so that the crank shaft can be rotated about its axis. Now connect an LED bulb or any small bulb with the input points of the electric motor. Now go on rotating the crankshaft. The ELECTRICITY will be generated from the motor as the motor will now start ACTING as Dynamo. The phenomenon which the motor is UNDERGOING is termed as reverse electromagnetic induction in which the magnet is in the stationary position and the conductor ROTATES resulting in energy generation. However, in electromagnetic induction the magnet MOVES and the conductor remains stationary

Discussion

7883.	An electric geyser rated 1500W, 250 V is connected to a 250v line mains. Calculate the electric current drawn by it, energy consumed by it in 50 hours and energy consumed if each unit coast Rs. 6.00.
Answer» Solution :Given P= 1500W V=250V i) CURRENT drawn `I = (P)/(V)= (1500)/(250)= 6A` ii) Electric energy consumed by gyser in ` "50 hours" = "Power" xx "time"` `= 1500 xx 50 = 75000 wH` Since 1KWH = 1 unit 75kwh = 75units. Energy consumed = 75 units iii) COST of one unit = 6.00 `"Cost 75 units" = 75 xx 6.00 = Rs.450.00`

Discussion

7884.	An electric bulb of 200 Omega draws a current of 1 ampere. Calculate the power of the bulb. The potential diffrence at is ends and the energy in kwh consumed in burining it for 5h.
Answer» Solution :POWER of the bulb Power of the bulb `P = PR = (1)^(2)x 200` P = 200W Energy CONSUMED by bulb in 5H in burning = Power x time = 200 x 5 = 1000wh = 1 kwh.

Discussion

7885.	An atom which has a mass number of 14 and has 8 neutrons is an:
Answer» isotope of oxygen isobar of oxygen isotope of CARBON isobar of carbon ANSWER :C

Discussion

7886.	An atom or a group of atoms which is responsible for chemical characteristics of an organic compound is called……………..
Answer» SOLUTION :FUNCTIONAL GROUP

Discussion

7887.	An atom of an element has nine electrons with l=0 value 18 electrons with l=1 value and 10 electrons with l=2 value . Calculate the atomic nuber of the element
Answer» 37 41 38 39 Solution : l=0 corresponds to's'subshell, l = 1 corresponds to'p'subshell, 1 = 2 corresponds to'd'subshell. The ATOM should possess'9''s'electrons, 18'p'electrons and 10'd' electrons. The electronic CONFIGURATION of the element should be `1s^2` `2s^2` `2p^6` `3s^2` `3p^6` `3d^(10)` `4s^2``4p^6` `5s^2`.The atomic number of the element should be 37.

Discussion

7888.	An atom of an element has 26 electrons and has a mass number 56. The nucleus of this atom contains neutrons.
Answer» 26 36 30 56 Answer :C

Discussion

7889.	An atom is said to be a non-metal if it ___________ electrons.
Answer» SOLUTION :GAINS or SHARES

Discussion

7890.	an atomis no longerindivisible .
Answer» ANSWER :TRUE

Discussion

7891.	An atom is
Answer» the smallest particle of MATTER known the smallest particle of a gas the smallest indivisible particle of an element that can TAKE part in a chemical REACTION radioactive emission Solution :the smallest indivisible particle of an element that can take part in a chemical reaction

Discussion

7892.	An atom has electronic configuration 2,8,7. To which of the following elements would be chemically similar ? (Atomic numbers are given in Parentheses).
Answer» N(7) F(9) P(15) AR(18) ANSWER :B

Discussion

7893.	An atom has electronic configuration 2, 8, 7 what is the atomic number of this element ?
Answer» SOLUTION :The ATOMIC NUMBER of this ELEMENT is 17.

Discussion

7894.	An atom has electronic configuration 2, 8, 7. (a) What is the atomic number of this element ? (b) To which of the following elements would it be chemically similar ? (Atomic numbers are given in parentheses.) N (7) F (9) P (15) Ar (18)
Answer» SOLUTION :The atomic NUMBER of this ELEMENT is 17 (2 + 8 + 7). (b) F (9) Electronic CONFIGURATION of F is 2, 7.]

Discussion

7895.	An atom has the electronic configuration 2, 8, 7. a] What is the atomic number of this element? b] To which of the following elements would it be chemically similar? (Atomic numbers are given in parenthesis) N (7), F (9), P (15), Ar (18)
Answer» SOLUTION :(a) 17 (B) F (9).

Discussion

7896.	An atom has electronic configuration 2, 8, 7. (a) What is the atomic number of this element ? (b) To which of the following elements would it be chemically similar? (Atomic numbers are given in parentheses.) N(71), F(9), P(15), Ar(18).
Answer» Solution :Chlorine has the electronic CONFIGURATION 2, 8, 7. (a) Atomic number of an element is the sum of number of electrons or protons in the element. THEREFORE, atomic number of the element is `2 + 8 + 7 = 17`. (b) Chlorine is a halogen. Another halogen PRESENT in the group is F(9). Therefore, chlorine is chemically similar to F(9).

Discussion

7897.	An atom has electronic configuration 2, 8, 7.(a) What is the atomic number of this element?(b)To which of the following elements would it be chemically similar? (Atomic numbers are given in parentheses)N (7)F (9)P (15)Ar (18)
Answer» Solution :(a) The atomic number of this ELEMENT is obtained by adding all the electrons present in its electronic configuration. ` therefore`Atomic number = 2 + 8 + 7 = 17 (b)The electronic configuration of the given element = 2, 8, 7 Valence electron in its ATOM = 7 This element will be chemically similar to that element which has the same valence electron (7). The electronic configuration of the above elements are: (i) N (7): 2,5 (5 valence electron) (II) F (9): 2, 7 (7 valence electron) (iii) P (15): 2, 8,5 (5 valence electron) (iv) Ar (18): 2, 8, 8 (8 valence electron) Clearly, F (9) has 7 valence electrons just like that of the given element. Hence, the given element of atomic number 17 will be chemically similar to the element fluorine (F) of atomicnumber 9.

Discussion

7898.	An atom has 16 neutrons in its nucleus. The Atomic no. of the element is 15 the mass num ber of the element is
Answer» 15 16 31 none of these ANSWER :C

Discussion

7899.	An atom has electronic configuration 2, 8, 2. (i) What is the atomic number of this element ? (ii) What is its valency ? (iii) To which of the following elements would it be chemically similar and why ? (Be-4, 0-8. Justify your answer.)
Answer» SOLUTION :(i) 12. (ii) 2. (iii) Be. Because Be has TWO electrons in its valence shell. GIVEN ELEMENT also has two electrons in its valence shell. Since valence electrons determine the chemical property, HENCE the given element has same chemical properties as that of Be.

Discussion

7900.	An atom gives up an electron to form a ______ ion.
Answer» SOLUTION :POSITIVE

Discussion

Explore topic-wise InterviewSolutions in .

An element has its electronic configuration as 2, 8, 2. Now anwswer the following questions : What is the group of this element?

An element has its electronic configuration as 2, 8, 2. Now anwswer the following questions : What is the atomic number of this element ?

An element has its electronic configuration as 2, 8, 2. Now anwswer the following questions : To which period does this element belong?

An element has electronic configuration 2,8,4. It will be classified as

An element has electrons configuration 2,8,4. It belong to which group and period of the Periodic Table

An element has atomic number 3. To which period of the periodic table does it belong?

An element has atomic no. 16 It will belong to which period of the periodic table ?

An element has atomic mass 93 g mol^(_1) and density 11.5 g cm^(-3). If the edge length of its unit cell is 300 pm, identify the type of unit cell.

Atomic number of element Z is 16. Is Z a metal or a non metal.

An element has 12 neutrons in its nucleus. To which group of the periodic table it will belong?

An element forms an oxide A_2O_3which is acidic in nature. Identify A as a metal or non-metal.

An element common to all acid is

An element combines with oxygen to give a compound with a high melting point. The compound is also soluble in water. The element is likely to be

An element combines with oxygen to form an oxide. This oxide dissolves in water. This aqueous solution changes blue litmus to red. Write the nature of the element (metal or nonmetal)

An element burns in oxygen to form its oxide which is soluble in water. This aqueous solution gives a pink colour with phenolphthalein. What conclusions do you draw from these observations?

An element belongs to group 17 and period 3 of the periodic table. Write the following:Its metallic and nonmetallic nature

An element becomes another element if the number of

An element B belongs to the second period and Group 13. Give the formula of the oxide.

An element A reacts with oxygen to form A2O. i] State the number of electrons in the outermost orbit of A. ii] To which group of the periodic table does A belong? iii] State whether A is a metal or a non-metal.

An element A reacts with oxygen to form A_2 O. (i) State the number of electrons in the outermost orbit of A. (ii) To which group of the periodic table does A belong? (iii) State whether A is a metal or a non-metal.

An element A reacts with water to form a compound B which is used in white washing. The compound B on heating forms an oxide C which on treatment with water gives back B. Identify A, B and C and give the reactions involved.

An element A forms two oxides AO and AO_2 . The oxide AO is neutral whereas the oxide AO_2is acidic in nature. Would you call element A a metal or a non-metal ?

An element A burns with golden flame in air. It reacts with another element B, atomic number 17to give a product C. An aqueous solution of the product C on electrolysis gives a compound D and liberates hydrogen. Identify A, B, C and D. Also write down the equations for the reactions involved.

An element A burns with golden flame in air. It reacts with another element B, atomic number 17 to give to product C. An aqueous solution of productC on electrolytes gives a compound D and liberates hydrogen, Identify A, B ,C and D Also write down the equation for the reactions involved.

An element ‘M’ has atomic number 11. a)Write its electronic configuration. b)State the group to which ‘M’ belongs c)is 'M' a metal or a non - metal ? d)Write the formula of its chloride.

An electron is revolving in an orbit with a veloc- ity of 5.46xx107 cm s^(-1) . Calculate the wave length associated with the electron.

An electron is present in a hydrogen atom in the ground state and another electron is present in a smgle electron species of beryllium. In both the species the distance between the nucleus and electren 18 same. Calculate the difference in their energies.

An electronhas mass thatis very muchlessthanproton.

An electrolyte and a nonelectrolyte .

An electric refrigerator rated 300 W is used for 8 hours a day. An electric iron box rated 750 Wis used for 2 hours a day. Calculate the cost of using these appliances for 30 days, if the cost of 1 kWh is Rs. 3/-

An electric refrigerator rated 400 W is used for 8 hours a day. An electric iron box rated 750 W is used for 2 hours a day. Calculate the cost of using these appliances for 30 days, if the cost of I kWh is Rs 3/-.

An electric motor is taken out from a toy ear. How do you convert this motor into a small electric generator? Compare the function of electric generator with the phenomenon of electromagnetic induction.

An electric geyser rated 1500W, 250 V is connected to a 250v line mains. Calculate the electric current drawn by it, energy consumed by it in 50 hours and energy consumed if each unit coast Rs. 6.00.

An electric bulb of 200 Omega draws a current of 1 ampere. Calculate the power of the bulb. The potential diffrence at is ends and the energy in kwh consumed in burining it for 5h.

An atom which has a mass number of 14 and has 8 neutrons is an:

An atom or a group of atoms which is responsible for chemical characteristics of an organic compound is called……………..

An atom of an element has nine electrons with l=0 value 18 electrons with l=1 value and 10 electrons with l=2 value . Calculate the atomic nuber of the element

An atom of an element has 26 electrons and has a mass number 56. The nucleus of this atom contains neutrons.

An atom is said to be a non-metal if it ___________ electrons.

an atomis no longerindivisible .

An atom is

An atom has electronic configuration 2,8,7. To which of the following elements would be chemically similar ? (Atomic numbers are given in Parentheses).

An atom has electronic configuration 2, 8, 7 what is the atomic number of this element ?

An atom has electronic configuration 2, 8, 7. (a) What is the atomic number of this element ? (b) To which of the following elements would it be chemically similar ? (Atomic numbers are given in parentheses.) N (7) F (9) P (15) Ar (18)

An atom has the electronic configuration 2, 8, 7. a] What is the atomic number of this element? b] To which of the following elements would it be chemically similar? (Atomic numbers are given in parenthesis) N (7), F (9), P (15), Ar (18)

An atom has electronic configuration 2, 8, 7. (a) What is the atomic number of this element ? (b) To which of the following elements would it be chemically similar? (Atomic numbers are given in parentheses.) N(71), F(9), P(15), Ar(18).

An atom has electronic configuration 2, 8, 7.(a) What is the atomic number of this element?(b)To which of the following elements would it be chemically similar? (Atomic numbers are given in parentheses)N (7)F (9)P (15)Ar (18)

An atom has 16 neutrons in its nucleus. The Atomic no. of the element is 15 the mass num­ ber of the element is

An atom has electronic configuration 2, 8, 2. (i) What is the atomic number of this element ? (ii) What is its valency ? (iii) To which of the following elements would it be chemically similar and why ? (Be-4, 0-8. Justify your answer.)

An atom gives up an electron to form a ______ ion.

An atom has 16 neutrons in its nucleus. The Atomic no. of the element is 15 the mass num ber of the element is