Q2: The energy of an electron in the ground state (n=1) for He+ ion is −x J, then that for an electron in (n = 2) state for Be3+ ion in J is
(a) −x
(b) −x/9
(c) −4x
(d) −4/9x [2024]
Ans: (a)
The energy levels of an electron in a hydrogen-like ion (an atom or ion with only one electron) can be quantified using the formula:
where:
En is the energy of the electron in the nth energy level,
Z is the atomic number (number of protons) of the ion,
13.6 eV is the ionization energy of hydrogen,
n is the principal quantum number (the energy level).
Since we need to compare this across different ions in different energy states, let's plug in some numbers:
For He+ (Helium ion):
Z = 2 (as helium has 2 protons)
n = 1 for ground state
However, the problem gives the energy in joules, and it's given a constant x.
So, x = 54.4 eV (converted to joules as needed).
Next, for the
Be3+ ion:
Z = 4 (as beryllium has 4 protons)
n = 2
Since initially x = 54.4 eV (or its equivalent in joules) for at He+ at n = 1, and now we have the same energy for at Be3+ at n = 2, the energy level in joules would also equate to x, just at a different energy state and ion.
So, the answer is:
Option A: −x.
Q1: The relation between nm, (nm = the number of permissible values of magnetic quantum number (m)) for a given value of azimuthal quantum number (l), is (NEET 2023)
(a)
(b) l = 2nm + 1
(c) nm = 2l2 + 1
(d) nm = l + 2
Ans: (a)
Values of nm(magnetic quantum number) for given azimuthal quantum number can be calculated as following
Q2: Select the correct Statements from the following : (NEET 2023)
A. Atoms of all elements are composed of two fundamental particles.
B. The mass of the electron is 9.10939×10−31 kg.
C. All the isotopes of a given elements show same chemical properties.
D. Protons and electrons are collectively known as nucleons.
E. Dalton's atomic theory, regarded the atom as an ultimate particle of matter.
Choose the correct answer from the options given below.
(a) C, D and E only
(b) A and E only
(c) B, C and E only
(d) A, B and C only
Ans: (c)
It is statement based question.
Statements B, C & E are correct.
(B) Mass of the electron is
(C) All the isotopes of given elements show same chemical properties.
(E) Dalton's atomic theory, regarded the atom as an ultimate particle of matter.
Q1: In radius of second Bohr orbit of the He+ ion is 105.8 pm, what is the radius of third Bohr orbit of Li2+ ion? (NEET 2022 Phase 1)
(a) 1.587 pm
(b) 158.7 Å
(c) 158.7 pm
(d) 15.87 pm
Ans: c
Q2: Identify the incorrect statement from the following. (NEET 2022 Phase 1)
(a) All the five 5d orbitals are different in size when compared to the respective 4d orbitals.
( b) All the five 4d orbitals have shapes similar to the respective 3d orbitals.
(c) In an atom, all the five 3d orbitals are equal in energy in free state.
(d) The shapes of dxy, dyz and dzx orbitals are similar to each other; and dx2
Ans: (d)
In an atom, all the five 3d orbitals are equal in energy in free state i.e., degenerate.
The shape of dx2 − y2 is different then shape of dz2
The size of orbital depends on principal quantum number 'n' therefore all the five 3d orbitals are different in size when compared to the respective 4d orbitals.
Shape of orbitals depends on azimuthal quantum number 'I' therefore shapes of 4d orbitals are similar to the respective 3d orbitals.
Q3: Match List-I with List-II : (NEET 2022 Phase 2)
Choose the correct answer from the options given below :
(a) (a) - (iii), (b) - (iv), (c) - (ii), (d) - (i)
(b) (a) - (iii), (b) - (iv), (c) - (i), (d) - (ii)
(c) (a) - (iv), (b) - (iii), (c) - (i), (d) - (ii)
(d) (a) - (iv), (b) - (iii), (c) - (ii), (d) - (i)
Ans: (a)
Q4: When electromagnetic radiation of wavelength 300 nm falls on the surface of a metal, electrons are emitted with the kinetic energy of 1.68
(h = 6.626
(a) 2.31
(b) 2.31
(c) 3.84
(d) 3.84
Ans: (a)
Q1: A particular station of All India Radio, New Delhi, broadcasts on a frequency of 1,368 kHz (kilohertz). The wavelength of the electromagnetic radiation emitted by the transmitter is : [speed of light, c = 3.0 x 108 ms-1] (NEET 2021)
(a) 2192 m
(b) 21.92 cm
(c) 219.3 m
(d) 219.2 m
Ans: (c)
Energy of electromagnetic radiation (E)
Q2: From the following pairs of ions which one is not an iso-electronic pair? (NEET 2021)
(a) Fe2+, Mn2+
(b) O2
(c) Na+, Mg2+
(d) Mn2+, Fe3+
Ans: (a)
Isoelectronic species have some number of electrons.
Q1: 4d, 5p, 5f and 6p orbitals are arranged in the order of decreasing energy. The correct option is (NEET 2019)
(a) 5f > 6p > 5p > 4d
(b) 6p > 5f > 5p > 4d
(c) 6p > 5f > 4d > 5p
(d) 5f > 6p > 4d > 5p
Ans: (a)
As per Aufbau principle (n + l rule), higher is the value of (n + l), greater will be the energy. When (n + l) values are same then which orbital have higher value of n will have more energy.
4d = 4 + 2 = 6
5p = 5 + 1 = 6
5f = 5 + 3 = 8
6p = 6 + 1 = 7
Hence, the correct order of decreasing energy will
be : 5f > 6p > 5p > 4d.
Q2: Which of the following series of transitions in the spectrum of hydrogen atom fall in visible region? (NEET 2019)
(a) Lyman series
(b) Balmer series
(c) Paschen series
(d) Brackett series
Ans: (b)
Q1: Which one is a wrong statement ? (NEET 2018)
(a) Total orbital angular momentum of electron in 's' orbital is equal to zero
(b) An orbital is designated by three quantum numbers while an electron in an atom is designated by four quantum numbers.
(c) The electronic configuration of N atom is
(d) The value of m for dz2 is zero
Ans: (c)
In degnerate orbital all unpaired electrons show same spin. So the correct configuration of N atom is
Q1: Which one is the wrong statement ? (NEET 2017)
(a) The uncertainty principle is
(b) Half filled and fully filled orbitals have greater stability due to greater exchange energy, greater symmetry and more balanced arrangement.
(c) The energy of 2s-orbital is less than the energy of 2p-orbital in case of hydrogen like atoms.
(d) de-Broglie's wavelength is given by where m = mass of the particle, v = group velocity of the particle.
Ans: (c)
In the case of hydrogen type atoms, energy depends on the principal quantum number only. Therefore 2-s orbital will have energy equal to 2-p orbital.
Q1: Two electrons occupying the same orbital are distinguished by : (NEET 2016 Phase 1)
(a) Spin quantum number
(b) Principal quantum number
(c) Magnetic quantum number
(d) Azimuthal quantum number
Ans: (a)
For any two electrons occupying the same orbital values of n, l and ml are same but ms is different [ + 1/2 and - 1/2]
Q2: How many electrons can fit in the orbital for which n = 3 and l = 1? (NEET 2016 Phase 2)
(a) 2
(b) 6
(c) 10
(d) 14
Ans: (a)
For n = 3 and l = 1, the subshell is 3p and a particular 3p orbital can accodomodate only 2 electrons.
Q3: Which of the following pairs of d-orbitals will have electron density along the axes ?
(a)
(b)
(c)
(d) (NEET 2016 Phase 2)
Ans: (c)
dx2 - y2 and dz2 orbitals have electron density along the axes.
Q1: The angular momentum of electron in 'd' orbital is equal to: (NEET / AIPMT 2015 Cancelled Paper)
(a) 0 h
(b) √6h
(c) √2h
(d) 2√3h
Ans: (b)
Angular momentum of electron in 'd‘ orbital =
Q2: The number of d-electrons in Fe2+ (Z = 26) is not equal to the number of electrons in which one of the following ?
(a) p - electrons in Ne (Z = 10)
(b) s - electrons in Mg (Z = 12)
(c) p - electrons in Cl (Z = 17)
(d) d - electrons in Fe (Z = 26) (NEET / AIPMT 2015 Cancelled Paper)
Ans: (c)
Number of d-electrons in Fe2+ = 6
Number of p-electrons in Cl = 11
Q3: Which is the correct order of increasing energy of the listed orbitals in the atom of titanium ? (At. no. Z = 22)
(a) 4s 3s 3p 3d
(b) 3s 3p 3d 4s
(c) 3s 3p 4s 3d
(d) 3s 4s 3p 3d (NEET / AIPMT 2015)
Ans: (c)
Ti (22)
Q1: Magnetic moment 2.83 BM is given by which of the following ions ?
(At. Nos. Ti = 22, Cr = 24, Mn = 25, Ni = 28) (NEET 2014)
(a) Cr3+
(b) Mn2+
(c) Ti3+
(d) Ni2+
Ans: (d)
Q2: What is the maximum number of orbitals that can be identified with the following quantum numbers ? n = 3,l= 1, ml = 0 (NEET 2014)
(a) 3
(b) 4
(c) 1
(d) 2
Ans: (c)
3p orbital can have n = 3, l = 1 and ml = 0.
Q3: Calculate the energy in joule corresponding to light of wavelength 45 nm :
(Planck's constant h = 6.63 × 10−34 Js; speed of light c = 3 × 108 ms−1) (NEET 2014)
(a) 4.42 × 10-15
(b) 4.42 × 10-18
(c) 6.67 × 1015
(d) 6.67 × 1011
Ans: (b)
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1. What is the basic structure of an atom? |
2. How do electrons move within an atom? |
3. What is the significance of the atomic number in an atom? |
4. How does the electron configuration of an atom affect its chemical behavior? |
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