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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 901. |
The sum of all the quantum number of helium atomm isA. 1B. 2C. 3D. 4 |
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Answer» Correct Answer - A `1He = 1s^(2), n = 1,l = 0 ,m = 0, s = 1//2, -1//2` `Sum = 1 + (1)/(2) - (1)/(2) = 1` |
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| 902. |
The lightest particle is //areA. ElectronB. ProtonC. NutronD. `beta`- particle |
| Answer» Correct Answer - A::D | |
| 903. |
The lightest radioactive isotope in periodic table isA. TritiumB. DeuteriumC. ProtiumD. All the above |
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Answer» Correct Answer - A Tritium is lighest radioactive isotope |
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| 904. |
The quantum numbers of most energetic electron in Ar atom when it is in first excited state isA. `2,1,0, +-1//2`B. `4,1,1,+-½`C. `4,0,0,+-1//2`D. `4,1,0,+-1//2` |
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Answer» Correct Answer - C quantum numbers concept |
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| 905. |
Which is the correct relationship-A. `E_(1)` of `H=1//2E_(2)` of `He^(+)=1//3E_(3)`of `Li^(2+)=1//4E_(4)`of `Be^(3+)`B. `E_(1)(H)=E_(2)(He^(+))=E_(3)(Li^(2+))=E_(4)(Be^(3+))`C. `E_(1)(H)=2E_(2)(He^(+))=3E_(3)(Li^(2+))=4E_(4)(Be^(3+))`D. No relation |
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Answer» Correct Answer - B `E_(n) = - 13.6 xx(Z^(2))/(n^(2))` `E_(1)(H) =-13.6xx(1)/(1)=-13.6eV` `E_(2)(He^(+))=-13.6xx(4)/(4)=-13.6eV` `E_(3)(Li^(2+))=-13.6xx(3^(2))/(3^(2))=-13.6eV` `E_(4)(Be^(3+))=-13.6xx(4^(2))/(4^(2))=-13.6eV` `therefore` Ans `B` |
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| 906. |
Atomic radius is to of the order of `10^(-8)` cm and nuclear radius is to order of `10^(-13)`cm. Calculate what fraction of atom is occupied by nucleus.A. `10^(-13)xx` atomic volumeB. `10^(-14)xx` atomic volumeC. `10^(-15)xx` atomic volumeD. `10^(-16)xx` atomic volume |
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Answer» Correct Answer - C volume `=(4)/(3)pi r^(3)` |
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| 907. |
Atomic radius is to of the order of `10^(-8)` cm and nuclear radius is to order of `10^(-13)`cm. Calculate what fraction of atom is occupied by nucleus. |
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Answer» Volume of nucleus `=(4)/(3)pir^(3)=(4)/(3)pi(10^-13)^(3)cm^(3)` Volume of atom `=(4)/(3)pi(10^(-8))^(3) cm^(3)`, `V_(N)/V_("Atom")=10^(-39)/10^(-24)=10^(-15)` `V_("Nucelus")=10^(-15)xxV_("Atom")` |
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| 908. |
Statement-1: For 1s-orbital the probaility density is maximum at the nucleus. Satement-2: Nuclear volume is small. |
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Answer» Correct Answer - a |
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| 909. |
Which of the following statement is correct ?A. `(n-1)` sub-shell has higher energy than m sub-shellB. `(n-1)d` sub-shell has lower energy than m sub-shellC. `(n+1)` sub-shell has lower energy then of sub-shellD. `nf` sub-shell has lower energy than (n + 1)` sub-shell |
| Answer» Correct Answer - b | |
| 910. |
If velocity of an electron in 1st orbit of H atoms is V , what will be the velocity in 3rd orbit of `Li^(2+)` ?A. vB. `(v)/(3)`C. 3vD. 9v |
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Answer» Correct Answer - A |
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| 911. |
The ratio of the energy of the electron in ground state of hydrogen to the electron in first excited state of `Be^(3+)` is :A. `1 : 4`B. `1 : 8`C. `1 : 16`D. `16 : 1` |
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Answer» Correct Answer - A (a) `E_n = - (13.6 Z^2)/(n^2) eV`, where `Z = "atomic number" = 4` `N = "number of orbits"` `Be^(3 +) (n = 2)` (first excited state) `E_1 = -13.6 eV, E_2 - 13.6 xx 16//4`. |
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| 912. |
If velocity of an electron in 1st orbit of H atoms is V , what will be the velocity in 3rd orbit of `Li^(2+)` ?A. `V`B. `V//3`C. `3V`D. `9V` |
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Answer» Correct Answer - A `V_(n)=2.188xx10^(6)xx(Z)/(n)m//sec` `(V_(3)(Li^(2+)))/(V_(1)(H))=(Z_(3)//n_(3))/(Z_(1)//n_(1))=(3//3)/(1//1)" "V(Li^(2+))=V` |
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| 913. |
The ratio of energy of the electron in ground state of hydrogen to the electron in first excited state of `Be^(3+)` isA. ` 1 : 4`B. `1 : 8`C. `1 : 16`D. `16 : 1` |
| Answer» Correct Answer - 1 | |
| 914. |
With what velocity should an `alpha ` paricle travel towards the nucleus of a copper atom so as to arrive at a distance `10^(-13)m` from the nucleus of the copper atom? |
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Answer» `(1)/2m_(alpha)v_(alpha)^(2)=(kz_(1)z_(2))/(r_("min")^(2))=(k(2e)k(63e))/r_("min")^(2)` `v_(alpha)=(k(2e)(63e))/(m_(alpha).r^(2)_("min")` `v_(alpha)=sqrt((2k.2e.63e)/(m_(alpha).r_("min")^(2)))=6.3xx10^(6)m//s` |
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| 915. |
The energy of an electron in the first Bohr orbit of H atom is `-13.6 eV` The potential energy value (s) of exxcited state(s) for the electron in the Bohr orbit of hydrogen is//areA. `-3.4 eV`B. `-4.2 eV`C. `6.8 eV`D. `+6.8 eV` |
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Answer» `E_(n) = (-13.6)/(n^(2))eV` when `n =2,E_(2) =(-13.6)/(4) = 3.4 eV` Hence (a) is the correct answer |
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| 916. |
If the value of `E=-78.4 "kcal//mol"`, the order of the orbit in hydrogen atom is-A. 4B. 3C. 2D. 1 |
| Answer» Correct Answer - 3 | |
| 917. |
If the value of `E=-78.4 "kcal//mol"`, the order of the orbit in hydrogen atom is-A. `4`B. `3`C. `2`D. `1` |
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Answer» Correct Answer - C `E=-78.4 kcal//mol` `E_(n)=-313.6xx(Z^(2))/(n^(2))kcal//mol` for `H` atoom `Z=1 " "-78.4=313.6xx(1)/(n^(2))` `n^(2)=(313.6)/(78.4)" "n=2` |
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| 918. |
In all, how many nodal plates are there in the atomic orbiitals for the principal quantum number `n = 3`? |
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Answer» Shell with `n = 3` has ` 1s (3s),3p(p_(x)p_(y)p_(z)) ` and `5d(d_(xy)d_(z)d_(y^(2) - y^(3)) ` and ` d_(z^(2)` x has no nodal plane Each of `p_(x)p_(y)p_(z)` has one nodel palne means a total of three nodal plases `d_(z^(2)` has no nodal palne Each of `d_(xy)d_(xz) d_(x)d_(x^(2) - y^(2)` has nodal plases Hence for `n = 3` a total of nodal planes are there . |
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| 919. |
If an electron in H atom has energy of `-76.4` kcal `"mol"^(-1)` .The orbit in which the electron is present isA. IstB. 2ndC. 3rdD. 4th |
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Answer» `E_(n) = (-313.6)/(n^(2)) kcal mol^(-1)` `rArr -78.4 = (-313.6)/(n^(2))` `:. N= 2` |
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| 920. |
The de-Broglie wavelength of a tennis ball mass ` 60 g` moving with a velocity of ` 10 m` per second is approximately :A. `10^(-33) `mB. `10^(-31)`mC. `10^(-16)` mD. `10^(-25)` m |
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Answer» Correct Answer - A |
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| 921. |
The de-Broglie wavelength of a tennis ball mass ` 60 g` moving with a velocity of ` 10 m` per second is approximately :A. `10^(-33)` metresB. `10^(-31)` metresC. `10^(-16)` metresD. `10^(-25)` metres |
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Answer» Correct Answer - A `lambda=h/"mv"=(6.63xx10^(-34))/(60xx10^(-3)xx10) =10^(-33)` m |
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| 922. |
Magnitude of K.E. in an orbit is equal toA. Half of the potential energyB. Twice of the potential energyC. One fourth of the potential energyD. None of these |
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Answer» Correct Answer - A K.E. of `e^-=1/2` of P.E. But K.E. is always positive . or `KE=-[1/2P.E.]=`-[Total Energy of system] |
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| 923. |
A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference V esu. If c and m are charge and mass of an electron repectively, then the value of `h//lambda` (where `lambda` is wavelength associated with electron wave) is given by :A. 2meVB. `sqrt(meV)`C. `sqrt(2meV)`D. meV |
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Answer» Correct Answer - C `K.E.=eV` `lambda=h/sqrt(2meV)` `h/lambda=sqrt(2meV)` |
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| 924. |
What is the ratio of mass an electron to the mass of a protonA. `1:2`B. `1:1`C. `1:1837`D. `1:3` |
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Answer» Correct Answer - C Electron `1/1837` time lighter than proton so their mass ratio will be 1:1837 |
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| 925. |
A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference V esu. If c and m are charge and mass of an electron repectively, then the value of `h//lambda` (where `lambda` is wavelength associated with electron wave) is given by :A. `sqrt(2meV)`B. `meV`C. `2emV`D. `sqrt(meV)` |
| Answer» Correct Answer - A | |
| 926. |
A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference V esu. If c and m are charge and mass of an electron repectively, then the value of `h//lambda` (where `lambda` is wavelength associated with electron wave) is given by :A. `2 meV`B. `sqrt(meV)`C. `sqrt(2meV)`D. `meV` |
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Answer» Correct Answer - C |
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| 927. |
Cathode rays do not travel in straight lines. Cathode rays do not penetrate through thick sheets.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is falseD. If assertion is false but reason is true. |
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Answer» Correct Answer - D (d) We know that cathode rays cast shadows of solid objects placed in their path. During experiment performed on these rays, fluorescence (flash of light) is observed in the region, outside the shadow. This shows that cathode rays travel in straight lines. We also know that cathode rays penetrate through a thin sheet of metals but are stopped by thick sheets. Therefore assertion is false but the reason is true. |
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| 928. |
X-rays are produced when a stream of electrons in an X-ray tube:A. Hits the glass wall of the tubeB. strikes the metal targetC. passes through a strong magnetic fieldD. none of the above |
| Answer» Correct Answer - B | |
| 929. |
Assertion : Cathode rays do not travel in straight lines. Reason : Cathode rays penetrate through thick sheets.A. If both assertion and reason are true and the reason is the correct explanation of the assertionB. If both assertion and reason are true but reason is not the correct explanation of the assertionC. If assertion is true but reason is falseD. If the assertion and reason both are false |
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Answer» Correct Answer - D We know tha cathode rays cast shadows of solid objects placed in their path. During experiment performed on these rays, fluorescene (flash of light) is observed in the region, outside the shadow. This shows that cathode rays travel in straight lines. We also know that cathode rays penetrate through a thin sheet of metals but are stopped by thick sheets. Therefore both Assertion and Reason are false. |
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| 930. |
What will be the difference in mass number if the number of neutrons halved and the number of electrons doubled in `._(6)^(12)C` |
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Answer» Mass no is the sum of protons and neutraons `{:(ln ._(6)^(12)C,"Initial","Final"),("protons":,6,6),("Neutrons":,6,3),("mass no":,12,9):}` Hence the decrease in mass no is `25.0%` |
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| 931. |
Assertion : Cathode rays are a stream of `alpha`-particles. Reason : They are generated under high pressure and high voltage.A. If both assertion and reason are true and the reason is the correct explanation of the assertionB. If both assertion and reason are true but reason is not the correct explanation of the assertionC. If assertion is true but reason is falseD. If the assertion and reason both are false |
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Answer» Correct Answer - D Both assertion and reason are false. Cathode rays are stream of electrons. They are generated through gases at low pressure and high voltage. |
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| 932. |
The energy per quantum associated with light of wave length `250 xx 10^(-9)m` isA. `7.95 xx 10^(-19)J`B. `7.95 xx 10^(-26)J`C. `3.93 xx 10^(-26)J`D. `3.93 xx 10^(-19)J` |
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Answer» Correct Answer - A `E = (hC)/(lambda)` |
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| 933. |
In a photoelectric experiment, the stopping potential 'V' is plotted against the frequency v of the incident light. The resulting curve is a straight line which makes and angle `theta` with the x-axis. Then `tan theta` will be equal to: (here `phi`=work function of the surface)A. `h//e`B. `e//h`C. `-phi//e`D. `eh//phi` |
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Answer» Correct Answer - A `eV = hv - hv_(0) rArr V = (h)/(e) v - (h)/(e) v_(0)` |
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| 934. |
Calculate the no of protons, neutrons and electron in `._(36)^(80)Br` |
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Answer» No. of protons =Atomic number `(Z) = 35` mass number of `(A) = 80` The species is neutral. So, no of electrons =35 No. of neutrons `=A-Z =80 - 35= 45` |
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| 935. |
The charge on the atom containing `17` protons, `18` neutrons and `18` electrons is.A. `+1`B. `-1`C. `-2`D. None |
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Answer» Correct Answer - B 1 electron is more |
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| 936. |
The charge on the atom containing `17` protons, `18` neutrons and `18` electrons is.A. `+ 1`B. `-2`C. `-1`D. zero |
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Answer» Correct Answer - C ( c) `Cl^-` has `17` protons, `18` neutrons and `18` electrons. |
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| 937. |
The frequency of a wave light is `1.0 xx 10^(6)sec^(-1)`. The wave length for this wave isA. `3 xx 10^(4)cm`B. `3 xx 10^(-4)cm`C. `6 xx 10^(4)cm`D. `6 xx 10^(6)cm` |
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Answer» Correct Answer - A `v = (c)/(lambda)` |
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| 938. |
The charge on the atom containing `17` protons, `18` neutrons and `18` electrons is.A. `+1`B. `-2`C. `1`D. Zero |
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Answer» Correct Answer - C `Cl^-` have 17 proton, 18 neutron , 18 electron. |
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| 939. |
An ion with mass number `56` contains `3` units of positive charge and `30.4%` more neutrons then electrons. Assign the symbol to this ion.A. `._(26)^(55)Fe^(3+)`B. `._(26)^(57)Fe^(3+)`C. `._(26)^(59)Fe^(3+)`D. `._(26)^(56)Fe^(3+)` |
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Answer» Correct Answer - D Let the number of electrons is `A^(+3) =x` |
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| 940. |
The ............ are arranged in the empty space around the ................ of the atom . |
| Answer» electrons, nucleus | |
| 941. |
Sodium atoms and sodium ions:A. are chemically similaryB. Both react vigorously with waerC. have same umber of electronsD. have same number of protons. |
| Answer» Correct Answer - D | |
| 942. |
Neutrino has:A. charge +1, mass 1B. charge 0, mass 0C. charge -1, mass 1D. charge 0, mass 1 |
| Answer» Correct Answer - B | |
| 943. |
Calculate the no of protons neutrons and electrons in `._(17)^(37)Cl` |
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Answer» No. of protons =Atomic number `(Z) = 17)` mass number `(A) = 37` No.of neutrons `=A-Z = 37-17 = 20` No. of electrons `=17` |
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| 944. |
In `._(17)^(35)Cl and ._(17)^(37)Cl`, which of the following is false?A. Both have 17 protonsB. Both have 17 electronsC. Both have 18 neutronsD. Both shwo same chemical properties. |
| Answer» Correct Answer - C | |
| 945. |
The number of electrons .............. or .............. by an atom determines the ............... of the element concerned . |
| Answer» lost , gained , valency | |
| 946. |
Why do `""_(17)^(35)Cl and ""_(17)^(37)Cl` have the same chemical properties though their atomic masses are different ? |
| Answer» Because they have the same number of valence electrons | |
| 947. |
During an experiment an `alpha`-particle and a proton are accelerated by same potential difference , their de Broglie wavelength ratio will be : (Take mass of photon = mass of neutron)A. `1:2`B. `1:4`C. `1:2 sqrt2`D. `1: sqrt2` |
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Answer» Correct Answer - C |
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| 948. |
The wave number for the longest wavelength transition in the Balmer series of atomic hydrogen isA. `15.2 xx 10^(6)m^(-1)`B. `13.6 xx 10^(6)m^(-1)`C. `1.5 xx 10^(6)m^(-1)`D. `1.3 xx 10^(6)m^(-1)` |
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Answer» Correct Answer - C `bar(v) = (1)/(lambda) = R_(H) [(1)/(n_(1)^(2))-(1)/(n_(2)^(2))]` |
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| 949. |
What will be the ratio of volume of `._(13)Al^(27)` nucleus to that of `._(11)Na^(23)`?A. 1.055B. 1.174C. Density of atoms should be known for calculationsD. 1 |
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Answer» Correct Answer - B |
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| 950. |
Nitrogen has an atomic number of 7 and oxygen has an atomic number of 8. The total number of electron in the nitrate ion `(NO_(3)^(-))` is : |
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Answer» Correct Answer - 32 |
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