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Can you explain the answer of this question below:The number of radial nodes for 3p orbital is __________.A:3B:4C:2D:1The answer is d.
|
Krishna Iyer answered |
► Number of radial nodes = n - 1 – 1
► For 3p orbital, n = 3 – 1 – 1 = 1
► Number of radial nodes = 3 – 1 – 1 = 1.
► For 3p orbital, n = 3 – 1 – 1 = 1
► Number of radial nodes = 3 – 1 – 1 = 1.
The nucleus of a tritium atom, 3H, contains- a)three protons
- b)three neutrons
- c)two protons and one neutron
- d)two neutrons and one proton
Correct answer is option 'D'. Can you explain this answer?
The nucleus of a tritium atom, 3H, contains
a)
three protons
b)
three neutrons
c)
two protons and one neutron
d)
two neutrons and one proton
|
Hansa Sharma answered |
Tritium (3H) is a radioactive isotope of hydrogen. The nucleus decays (by emitting an electron and an antineutrino), changing from a triton (one proton and two neutrons) to a 3He nucleus (two protons and one neutron).
Electronic configuration of the element having atomic number 24.- a)
- b)
- c)
- d)
Correct answer is option 'C'. Can you explain this answer?
Electronic configuration of the element having atomic number 24.
a)
b)
c)
d)
|
Ananya Sarkar answered |
atomic no 24 is of Cr. Due to half filled orbital stability it doesnot follow Afbau rule so its configuration is
Thomson’s plum pudding model explained:
- a) Existence of electrons
- b)Electrical neutrality of an atom
- c)Existence of atoms
- d)Electrons move in fixed circular orbits
Correct answer is option 'B'. Can you explain this answer?
Thomson’s plum pudding model explained:
a)
Existence of electrons
b)
Electrical neutrality of an atom
c)
Existence of atoms
d)
Electrons move in fixed circular orbits
|
Raghav Bansal answered |
Postulates of Thomson’s atomic model
- An atom consists of a positively charged sphere with electrons filled into it. The negative and positive charge present inside an atom are equal and as a whole, an atom is electrically neutral.
- Thomson’s model of the atom was compared to plum pudding and watermelon. He compared the red edible part of the watermelon to positively charged sphere whereas the seeds of watermelon to negatively charged particles.
One of the orbitals is non-directional- a)s- orbital
- b)f- orbital
- c)d- orbital
- d)p- orbital
Correct answer is option 'A'. Can you explain this answer?
One of the orbitals is non-directional
a)
s- orbital
b)
f- orbital
c)
d- orbital
d)
p- orbital
|
Gaurav Kumar answered |
s orbital is spherically symmetrical hence non directional.
Which of the following sets of quantum numbers is correct for an electron in 4f orbital ? [AIEEE- 2004]- a) n = 4, l = 3 , m = + 4, s = +
- b)n = 4, l = 4 , m = - 4, s = -
- c)n = 4, l = 3 , m = + 1, s = +
- d)n = 4, l = 3 , m = - 2, s = +
Correct answer is option 'C,D'. Can you explain this answer?
Which of the following sets of quantum numbers is correct for an electron in 4f orbital ? [AIEEE- 2004]
a)
n = 4, l = 3 , m = + 4, s = +
b)
n = 4, l = 4 , m = - 4, s = -
c)
n = 4, l = 3 , m = + 1, s = +
d)
n = 4, l = 3 , m = - 2, s = +
|
Suresh Iyer answered |
For 4f orbital electrons, n = 4
s p d f
l = 3 (because 0 1 2 3 )
m = +3, +2, +1, 0, –1, –2, –3
s = ±1/2.
Which of the following radiation has the shortest wavelength.- a)Infra red
- b)ultraviolet
- c)microwave
- d)X-ray
Correct answer is option 'D'. Can you explain this answer?
Which of the following radiation has the shortest wavelength.
a)
Infra red
b)
ultraviolet
c)
microwave
d)
X-ray
|
|
Gaurav Kumar answered |
Radio waves, infrared rays, visible light, ultraviolet rays, X-rays, and gamma raysare all types of electromagnetic radiation. Radio waves have the longest wavelength, and gamma rays have the shortest wavelength.
Energy change associated per mole of atoms with an atomic transition giving rise to radiations of 
What is the value of x?
Correct answer is '4'. Can you explain this answer?
Energy change associated per mole of atoms with an atomic transition giving rise to radiations of What is the value of x?
What is the value of x?
|
Naina Sharma answered |
Energy = n.hv
where,
n = 1 mole or 6.023 × 1023 atoms
h = 6.626×10-34 J.sec
v (frequancy) = 1 Hz
where,
n = 1 mole or 6.023 × 1023 atoms
h = 6.626×10-34 J.sec
v (frequancy) = 1 Hz
⇒ E = 6.023 ×1023 × 6.626×10-34 × 1 = 3.91 × 10-10
so approximately value of x = 4.
so approximately value of x = 4.
An element has 18 electrons, and 20 .neutrons. Its charge is —2. What is its mass number?- a)32
- b)38
- c)39
- d) 40
Correct answer is option 'C'. Can you explain this answer?
An element has 18 electrons, and 20 .neutrons. Its charge is —2. What is its mass number?
a)
32
b)
38
c)
39
d)
40
|
Knowledge Hub answered |
Number of orbitals in a shell = n2 = (5)2 = 25
Consider the following transitions n = 1 to n = 2 and then, n = 2 to n = 3.
Then- a)
- b)
- c)
- d)
Correct answer is option 'A,C,D'. Can you explain this answer?
Consider the following transitions n = 1 to n = 2 and then, n = 2 to n = 3.
Then
a)
b)
c)
d)
|
Lavanya Menon answered |
Energy values are additives i.e.
Hence, options A, C, D are correct.
Hence, options A, C, D are correct.
The wavelength of light that has a frequency of 1.20 × 1013s-1 is __________ m.- a)2.50 × 10-5
- b)0.0400
- c)25.0
- d)12.0
Correct answer is option 'A'. Can you explain this answer?
The wavelength of light that has a frequency of 1.20 × 1013s-1 is __________ m.
a)
2.50 × 10-5
b)
0.0400
c)
25.0
d)
12.0
|
|
Krishna Iyer answered |
The speed of all form of electromagnetic wave is related by the equation c = λ.v, whereby, λ = 3.0 x 108 / 1.2 x 1013 = 2.5 x 10 -5 m.
An cation A3+ has 18 electrons. Write the atomic number of A.- a)15
- b)24
- c)12
- d)21
Correct answer is option 'D'. Can you explain this answer?
An cation A3+ has 18 electrons. Write the atomic number of A.
a)
15
b)
24
c)
12
d)
21
|
|
Lavanya Menon answered |
3+ charge means no of electrons will be 3 less than no. of protons. So no. of protons will be 21. So atomic no. is 21.
The nucleus of helium contains- a) Four protons
- b) Four neutrons
- c) Four protons and two electrons
- d) Two neutrons and two protons
Correct answer is option 'D'. Can you explain this answer?
The nucleus of helium contains
a)
Four protons
b)
Four neutrons
c)
Four protons and two electrons
d)
Two neutrons and two protons
|
Ayush Joshi answered |
A helium nucleus is made of two protons and two neutrons.
They both have strong interactions.
A helium nucleus has a charge +2.
An atom has a mass of 0.02 kg & uncertainity in its velocity is 9.218 × 10-6 m/s then uncertainity in position is (h = 6.626 × 10-34 J - s) [AIEEE- 2002]- a)2.86 × 10-28 m
- b) 2.86 × 10-32 cm
- c)1.5 × 10-27 m
- d)3.9 ×10-10 m
Correct answer is option 'A'. Can you explain this answer?
An atom has a mass of 0.02 kg & uncertainity in its velocity is 9.218 × 10-6 m/s then uncertainity in position is (h = 6.626 × 10-34 J - s) [AIEEE- 2002]
a)
2.86 × 10-28 m
b)
2.86 × 10-32 cm
c)
1.5 × 10-27 m
d)
3.9 ×10-10 m
|
|
Priya Deshpande answered |
∆x*∆mv=h/4π
Which of the following electronic transitions requires that the greatest quantity of energy be absorbed by a hydrogen atom ?- a)n = 1 to n = 2
- b)n = 2 to n = 4
- c)n = 3 to n = 6
- d)n = 3 to n = ∞
Correct answer is option 'A'. Can you explain this answer?
Which of the following electronic transitions requires that the greatest quantity of energy be absorbed by a hydrogen atom ?
a)
n = 1 to n = 2
b)
n = 2 to n = 4
c)
n = 3 to n = 6
d)
n = 3 to n = ∞
|
|
Naina Sharma answered |
Therefore, electronic transition (a) requires greatest quantity of energy.
Atomic mass of an element is equal to the sum of?- a) Electron and neutron
- b) Electron and proton
- c) Proton and neutron
- d) None of the above
Correct answer is option 'C'. Can you explain this answer?
Atomic mass of an element is equal to the sum of?
a)
Electron and neutron
b)
Electron and proton
c)
Proton and neutron
d)
None of the above
|
|
Neha Joshi answered |
Atomic Mass is the sum of no. of protons and neutrons.
Direction (Q. Nos. 9-11) This section contains 3 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONE or MORE THANT ONE is correct.Q. Select the correct statement(s).- a)Electromagnetic radiation is a form of energy consisting of oscillating electric and magnetic fields
- b)Visible light is a form of electromagnetic radiation
- c)The electromagnetic spectrum of sunlight received at the Earth's surface differs from that emitted by the Sun
- d)Ultraviolet radiation is absorbed in the stratosphere by ozone and oxygen
Correct answer is option 'A,B,C,D'. Can you explain this answer?
Direction (Q. Nos. 9-11) This section contains 3 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONE or MORE THANT ONE is correct.
Q. Select the correct statement(s).
a)
Electromagnetic radiation is a form of energy consisting of oscillating electric and magnetic fields
b)
Visible light is a form of electromagnetic radiation
c)
The electromagnetic spectrum of sunlight received at the Earth's surface differs from that emitted by the Sun
d)
Ultraviolet radiation is absorbed in the stratosphere by ozone and oxygen
|
|
Geetika Shah answered |
Option A: Oscillations travel through space at a velocity of light, thus electromagnetic radiation is in the form of energy E = hv.
Option B: Radiowaves, microwaves, X-rays, and visible light are part of the Electromagnetic radiation spectrum.
Option C: Some of the radiations are absorbed in the atmosphere, hence the spectrum differs.
Option D: Ozone layer absorbs ultraviolet radiation.
Option B: Radiowaves, microwaves, X-rays, and visible light are part of the Electromagnetic radiation spectrum.
Option C: Some of the radiations are absorbed in the atmosphere, hence the spectrum differs.
Option D: Ozone layer absorbs ultraviolet radiation.
Hence, options A, B, C, and D are correct.
Direction (Q. Nos. 1-11) This section contains 11 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONLY ONE option is correct.Which of the following is correct?- a)1H1 and 2He3 are isotopes
- b)6C14 and 7N14 are isotopes
- c)19K39 and 20Ca40 are isotones
- d)9F19 and 11Na24 are isodiaphers
Correct answer is option 'C'. Can you explain this answer?
Direction (Q. Nos. 1-11) This section contains 11 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONLY ONE option is correct.
Which of the following is correct?
a)
1H1 and 2He3 are isotopes
b)
6C14 and 7N14 are isotopes
c)
19K39 and 20Ca40 are isotones
d)
9F19 and 11Na24 are isodiaphers
|
|
Raghav Bansal answered |
Because isotones means the same number of neutron, So, from the question, option c is right, number of neutron in k is,39-19= 20,and,the number of neutron in ca is also 40-20=20 so it is isotones.
In the absorption spectrum, the wavelengths which are absorbed, are missing and they appear as:- a)Bright lines
- b)Light bands
- c)Bright bands
- d)Dark lines
Correct answer is option 'D'. Can you explain this answer?
In the absorption spectrum, the wavelengths which are absorbed, are missing and they appear as:
a)
Bright lines
b)
Light bands
c)
Bright bands
d)
Dark lines
|
|
Riya Banerjee answered |
Light not absorbed by the sample will, as before, be separated (dispersed) into its component wavelengths (colors) by the prism. The appearance of the spectrum will resemble that obtained without the sample in place, with the exception that those wavelengths which have been absorbed are missing, and will appear as dark lines within the spectrum of colors. If a piece of the photographic film is used instead of the card, the absorption spectrum can be recorded.
The energy associated with the transition of an electron from the n=1 state to the n=3 state of H atoms is:- a)+1.74 x 10-17 Joules.
- b)-1.94 x 10-18 Joules.
- c)+1.94 x 10-18 Joules.
- d)-1.74 x 10-17 Joules.
Correct answer is option 'C'. Can you explain this answer?
The energy associated with the transition of an electron from the n=1 state to the n=3 state of H atoms is:
a)
+1.74 x 10-17 Joules.
b)
-1.94 x 10-18 Joules.
c)
+1.94 x 10-18 Joules.
d)
-1.74 x 10-17 Joules.
|
|
Lavanya Menon answered |
The formula to calculate the excitation energy is 13.6Z2(1/n12-1/n22), but this gives value in eV. To convert it in Joules we divide it by 6.24×1018 Here, Z=1,n1=1,n2=3 Putting these values in above formula we have, [13.6×1(1-1/9)]/6.24×1018 =(13.6×8×10-18)/(9×6.24) =1.94×10-18 Hence, the correct answer is C.
A proton accelerated from rest through a potential difference of 'V' volts has a wavelength λ associated with it. An alpha particle in order to have the same wavelength must be accelerated from rest through a potential difference of - a)V volt
- b)4V volt
- c)2V volt
- d)V/8 volt
Correct answer is option 'D'. Can you explain this answer?
A proton accelerated from rest through a potential difference of 'V' volts has a wavelength λ associated with it. An alpha particle in order to have the same wavelength must be accelerated from rest through a potential difference of
a)
V volt
b)
4V volt
c)
2V volt
d)
V/8 volt
|
Sonal Dey answered |
Direction (Q. Nos. 16 - 19) This section contains 4 questions. when worked out will result in an integer from 0 to 9 (both inclusive)Q. The energy of an electron in the first Bohr orbit of H-atom is -13.6 eV. What is the possible value of quantum number for the excited state to have energy -3.4 eV?
Correct answer is '2'. Can you explain this answer?
Direction (Q. Nos. 16 - 19) This section contains 4 questions. when worked out will result in an integer from 0 to 9 (both inclusive)
Q. The energy of an electron in the first Bohr orbit of H-atom is -13.6 eV. What is the possible value of quantum number for the excited state to have energy -3.4 eV?
|
Pooja Shah answered |
For Bohr radius;
E = -13.6×Z2/ n2
For H atom, Z=1 and given energy = -3.4
So, we have, -3.4 = -13.6/n2
Or n = 2
E = -13.6×Z2/ n2
For H atom, Z=1 and given energy = -3.4
So, we have, -3.4 = -13.6/n2
Or n = 2
Daltons atomic theory could not explain one of the following- a)Law of multiple Proportions,
- b)Law of conservation of mass
- c)Law of constant composition
- d)Discovery of sub-atomic particles
Correct answer is option 'D'. Can you explain this answer?
Daltons atomic theory could not explain one of the following
a)
Law of multiple Proportions,
b)
Law of conservation of mass
c)
Law of constant composition
d)
Discovery of sub-atomic particles
|
Om Desai answered |
Dalton’s atomic theory stated that atoms were indivisible. However, the discovery of subatomic particles (such as protons, electrons, and neutrons) disproved this postulate.
For Balmer series,the initial state n1 is :- a)4
- b)2
- c)3
- d)1
Correct answer is option 'B'. Can you explain this answer?
For Balmer series,the initial state n1 is :
a)
4
b)
2
c)
3
d)
1
|
|
Pooja Shah answered |
The Balmer series just sets n1 = 2, which means the value of the principal quantum number (n) is two for the transitions being considered. Balmer’s formula can therefore be written:
1/λ = RH ((1/22) − (1 / n22))
- a)333 m
- b)3.03 x 10-3m
- c)330 m
- d)3300 m
Correct answer is 'A'. Can you explain this answer?
|
|
Pooja Shah answered |
Direction (Q. Nos. 12 and 13) This section contains a paragraph, wach describing theory, experiments, data etc. three Questions related to paragraph have been given.Each question have only one correct answer among the four given ptions (a),(b),(c),(d)A hypothetical electromagnetic wave is pictured here.
Q. Energy associated with this wave is- a)4.24 x 10-19J
- b)2.12 x 10-19J
- c)1.06 x 10-19J
- d)8.49 x 10-19J
Correct answer is option 'A'. Can you explain this answer?
Direction (Q. Nos. 12 and 13) This section contains a paragraph, wach describing theory, experiments, data etc. three Questions related to paragraph have been given.Each question have only one correct answer among the four given ptions (a),(b),(c),(d)
A hypothetical electromagnetic wave is pictured here.
Q. Energy associated with this wave is
a)
4.24 x 10-19J
b)
2.12 x 10-19J
c)
1.06 x 10-19J
d)
8.49 x 10-19J
|
|
Hansa Sharma answered |
A to E makes one complete wave.
The number of radial nodes for 3p orbital is __________.- a)3
- b)4
- c)2
- d)1
Correct answer is 'D'. Can you explain this answer?
The number of radial nodes for 3p orbital is __________.
a)
3
b)
4
c)
2
d)
1
|
Amrita Kumar answered |
Number of radial nodes = n-1 – 1
For 3p orbital, n = 3 – 1 – 1 = 1
Number of radial nodes = 3 – 1 – 1 = 1.
For 3p orbital, n = 3 – 1 – 1 = 1
Number of radial nodes = 3 – 1 – 1 = 1.
Values of e/m (charge/mass) in the categories alpha particle (α), electron (e) and protons (p) increase in the order:
- a)α < e < p
- b)p < e < α
- c)e < α < p
- d)α< p < e
Correct answer is option 'D'. Can you explain this answer?
Values of e/m (charge/mass) in the categories alpha particle (α), electron (e) and protons (p) increase in the order:
a)
α < e < p
b)
p < e < α
c)
e < α < p
d)
α< p < e
|
|
Hansa Sharma answered |
E/m values of particle (α), electron (e) and protons (p) increase in the order α< p < e
Isobars are the atoms with- a)same atomic number but different number of neutrons
- b)same mass number but different atomic number
- c)same atomic number but different mass number
- d)same number of neutrons but different mass number
Correct answer is option 'B'. Can you explain this answer?
Isobars are the atoms with
a)
same atomic number but different number of neutrons
b)
same mass number but different atomic number
c)
same atomic number but different mass number
d)
same number of neutrons but different mass number
|
|
Nandini Patel answered |
Isobars are atoms (nuclides) of different chemical elements that have the same number of nucleons. Correspondingly, isobars differ in atomic number (or number of protons) but have the same mass number.
where, a and b are constants.
The nature of positive rays depends on?
- a)The nature of discharge tube.
- b)The nature of residual gas.
- c)The nature of electrode.
- d)All of above
Correct answer is option 'B'. Can you explain this answer?
The nature of positive rays depends on?
a)
The nature of discharge tube.
b)
The nature of residual gas.
c)
The nature of electrode.
d)
All of above
|
|
Om Desai answered |
- The nature of positive rays produced in a vacuum discharge tube depends upon the nature of the gas-filled.
- The positive rays consist of positive ions obtained by removing one or more electrons from gas molecules.
How much energy is needed to ionize a hydrogen atom if electron is present in n=1 orbit?- a)13.6 eV
- b)10.2 eV
- c)3.4eV
- d)1 eV
Correct answer is option 'A'. Can you explain this answer?
How much energy is needed to ionize a hydrogen atom if electron is present in n=1 orbit?
a)
13.6 eV
b)
10.2 eV
c)
3.4eV
d)
1 eV
|
|
Pooja Shah answered |
For hydrogen Z=1,
and n is given as 1,
Then
E= -13.6 × n power 2/ Z.
E= - 13.6 × 1 power 2/ 1.
E= -13.6e.v.
and n is given as 1,
Then
E= -13.6 × n power 2/ Z.
E= - 13.6 × 1 power 2/ 1.
E= -13.6e.v.
According to Bohr's theory, the angular momentum of an electron in 5th orbit is - [AIEEE 2006]- a)1.0 h/π
- b)10 h/π
- c)2.5 h/π
- d)25 h/π
Correct answer is option 'C'. Can you explain this answer?
According to Bohr's theory, the angular momentum of an electron in 5th orbit is - [AIEEE 2006]
a)
1.0 h/π
b)
10 h/π
c)
2.5 h/π
d)
25 h/π
|
|
Lavanya Menon answered |
The angular momentum (mvr) of electron in nth orbit is equal to nh/2π
For the electron in 5th orbit
For the electron in 5th orbit
The energy of a photon of light has what kind of proportionality to its frequency and its wavelength.- a)directly, inversely
- b)inversely, directly
- c)inversely, inversely
- d)directly, directly
Correct answer is option 'A'. Can you explain this answer?
The energy of a photon of light has what kind of proportionality to its frequency and its wavelength.
a)
directly, inversely
b)
inversely, directly
c)
inversely, inversely
d)
directly, directly
|
|
Pooja Shah answered |
As E=h(frequency) E is directly proportional to frequency and as frequency = speed of light / wavelength frequency is inversely proportional to wavelength.
Uncertainty in position of a particle of 25 g in space is 10-5 m. Hence uncertainty in velocity (ms-1) is (Planck's constant h = 6.6 × 10-34 Js) [AIEEE- 2002]- a)2.1 × 10-28
- b)2.1 × 10-34
- c)0.5 × 10-34
- d)5.0 × 20-24
Correct answer is option 'A'. Can you explain this answer?
Uncertainty in position of a particle of 25 g in space is 10-5 m. Hence uncertainty in velocity (ms-1) is (Planck's constant h = 6.6 × 10-34 Js) [AIEEE- 2002]
a)
2.1 × 10-28
b)
2.1 × 10-34
c)
0.5 × 10-34
d)
5.0 × 20-24
|
|
Neha Joshi answered |
∆p×∆x = h/4π
Or ∆v = h/4π∆xm (since p = mv)
=6.6×10-34Js/4×3.14×25×10-3kg ×10-5
by solving this your answer is 2.1×10-28
Or ∆v = h/4π∆xm (since p = mv)
=6.6×10-34Js/4×3.14×25×10-3kg ×10-5
by solving this your answer is 2.1×10-28
Most penetrating radiation of radioactive element is:- a) β — rays
- b) α — rays
- c) x — rays
- d) γ — rays
Correct answer is option 'D'. Can you explain this answer?
Most penetrating radiation of radioactive element is:
a)
β — rays
b)
α — rays
c)
x — rays
d)
γ — rays
|
Anjana Sharma answered |
Alpha rays as the least penetrating, followed by beta rays, followed by gamma rays as the most penetrating.
Energy of H–atom in the ground state is -13.6 eV , Hence energy in the second excited state is–
a) -1.51 eV
b) -3.4 eV
c) -6.8 eV
d) -4.3 eV
Correct answer is 'A'. Can you explain this answer ?
|
|
Neha Joshi answered |
The formula to calculate the energy is minus 13.6 multiply by z2 divided by n2.Here in second excited state n is equal to 3 and z for hydrogen is 1. So -13.6/9 = -1.51 ev
Calculate the wavelength of light that corresponds to the radiation that is given off during the transition of an electron from the n = 5 to n = 2 state of the hydrogen atom.- a)434 nm
- b)275 nm
- c)305 nm
- d)183 nm
Correct answer is option 'A'. Can you explain this answer?
Calculate the wavelength of light that corresponds to the radiation that is given off during the transition of an electron from the n = 5 to n = 2 state of the hydrogen atom.
a)
434 nm
b)
275 nm
c)
305 nm
d)
183 nm
|
|
Hansa Sharma answered |
1/wavelength =RH x z2 x (1/22-1/52) =109677 x 1 x (1/4-1/25) =109677 x 21/100 =2303.2m wavelength=1/2303.2m =1/2303.2 x 107nm =434.1nm~434nm
Increasing order of magnetic moment among the following species is __________ .Na+, Fe+3, Co2+, Cr+2- a)Na+<Fe+3<Co2+ <Cr+2
- b)Na+<Co2+<Cr2+ <Fe+3
- c)Na+<Cr2+<Co2+ <Fe+3
- d)Na+<Fe3+<Cr2+ <Co+2
Correct answer is option 'B'. Can you explain this answer?
Increasing order of magnetic moment among the following species is __________ .
Na+, Fe+3, Co2+, Cr+2
a)
Na+<Fe+3<Co2+ <Cr+2
b)
Na+<Co2+<Cr2+ <Fe+3
c)
Na+<Cr2+<Co2+ <Fe+3
d)
Na+<Fe3+<Cr2+ <Co+2
|
|
Nitin Khanna answered |
Na+, Co+2, Cr2+, Fe+3
we get Na+, Co+2, Cr2+, Fe+3
we get Na+, Co+2, Cr2+, Fe+3
The total energy of an electron in the nth orbit of a hydrogen atom is given by the formula
En = -13.6 eV/n2. What does the negative energy for an electron indicate?- a)Energy of electron in an atom is lower than energy of an electron far away from nucleus
- b)The electron has a negative charge.
- c)The electron is far away from nucleus
- d)Electrons have both wave and particle-like properties.
Correct answer is option 'A'. Can you explain this answer?
The total energy of an electron in the nth orbit of a hydrogen atom is given by the formula
En = -13.6 eV/n2. What does the negative energy for an electron indicate?
En = -13.6 eV/n2. What does the negative energy for an electron indicate?
a)
Energy of electron in an atom is lower than energy of an electron far away from nucleus
b)
The electron has a negative charge.
c)
The electron is far away from nucleus
d)
Electrons have both wave and particle-like properties.
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Gaurav Kumar answered |
The negative sign means that the energy of the electron in the atom is lower than the energy of a free electron at rest. A free electron at rest is an electron that is infinitely far away from the nucleus and is assigned the energy value zero.
Which model describes that there is no change in the energy of electrons as long as they keep revolving in the same energy level and atoms remains stable?- a)Rutherford Model
- b)Bohr’s Model
- c)J.J Thomson Model
- d)None of the above
Correct answer is option 'B'. Can you explain this answer?
Which model describes that there is no change in the energy of electrons as long as they keep revolving in the same energy level and atoms remains stable?
a)
Rutherford Model
b)
Bohr’s Model
c)
J.J Thomson Model
d)
None of the above
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Suresh Reddy answered |
Bohr Model of atom:
- An atom is made up of three particles: Electrons, neutrons and protons.
- The protons and neutrons are located in a small nucleus at the centre of the atom.
- The electrons revolve rapidly around the nucleus at the centre of the atom.
- There is a limit to the number of electrons that each energy level can hold.
- Each energy level is associated with a fixed amount of energy.
- There is no change in the energy of electrons as long as they keep revolving in the same energy level.
Bohr explained the stability through the concept of revolution of electrons in different energy levels.
The change in the energy of an electron occurs when it jumps from lower to higher energy levels. When it gains energy, it excites from lower to higher and vice versa.
Thus energy is not lost and the atom remains stable.
The change in the energy of an electron occurs when it jumps from lower to higher energy levels. When it gains energy, it excites from lower to higher and vice versa.
Thus energy is not lost and the atom remains stable.
The energy associated with the first orbit in the hydrogen atom is -2.18 x 10−18 J/atom. What is the energy associated with the fifth orbit?
a) -7.72 ×10−20 J/atom
b) -5.72 ×10−20 J/atom
c) -3.72 ×10−20 J/atom
d) -8.72 ×10−20 J/atom
Correct answer is 'D'. Can you explain this answer?
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Geetika Shah answered |
Energy for any n shell = -2.18 x 10−18 )/n'2 (') stands for raise to the power of therefore, E associated with 5 orbit = -2.18 x 10−18/52 = -2.18 × 10-18/25 = -218 × 10-20/25 = -8.72 x 10-20J/atom
The nature of positive rays depends on?- a) The nature of discharge tube.
- b) The nature of residual gas
- c) All of above.
- d) The nature of electrode
Correct answer is option 'B'. Can you explain this answer?
The nature of positive rays depends on?
a)
The nature of discharge tube.
b)
The nature of residual gas
c)
All of above.
d)
The nature of electrode
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Abhiram Choudhary answered |
The positive charges in these rays, other than negative cathode rays (which are electrons), depend on the gas that is used because they are cations - atoms with mostly one electron missing and thus one positive charge. So, if you accelerate, argon cations and protons over the same electric potential, the particles in the rays will have the same kinetic energy, but the argon ions will be much slower, as they are much heavier than the protons.
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