2. Structure of Atom Flashcards
Cathode rays originate from cathode. T/F
T
Charge to mass ratio was determined by the scientist -
JJ Thomson
Charge to mass ratio was determined by the scientist -
RA Milikan
Neutron was discovered by the scientist -
Chadwick
Charge of electron is -
- 1.6 * 10 ^ - 19 * C
Mass of electron is - (NEET 2023)
9.1 *10 ^ - 31 * kg
Mass of proton is -
1.67 * 10 ^ - 27 * kg
Rutherford gold foil was _______ atoms thick.
1000
Define isobars
atoms with same mass number but different atomic number
All the isotopes of a given element show same chemical behaviour. T/F (NEET 2023)
T
The radius of nucleus are usually expressed in terms of _______ Unit
fermi
Define wave number
l / lambda
SI unit of wave number is -
m ^ - 1
Wavelength of visible spectrum of light varies from ______ nm to _____ nm.
400-750
What is a black body?
The ideal body, which emits and absorbs radiations of all frequencies, is called a black body
Planck constant value -
6.626 x 10-34 Js
Work function is equal to -
hv₀
Planck’s law -
E = hv
Photoelectric effect equation -
hv = hv₀ + mv²/2
Balmar series is described by the formula -
Rydberg constant value -
109,677 cm-¹ or 2.18 x 10-¹⁸ J
The name of respective series for n₁ = 1, 2, 3, 4, 5, 6 is -
Lyman, Balmer, Paschen, Bracket, Pfund,
Humphrey
Which series of transitions in the spectrum of H atom falls in visible region? (NEET) (JEE 2021)
Balmar
According to Bohr, the angular momentum of an electron in a given stationary state can be expressed as
mur = nh/21π
rn = _______ (NEET 2022)
rn = agn²/Z where a₀ = 52.9 pm
En =
-218 x 10-¹⁸ (Z²/n²)
Velocity(Vn) =
- 2.18 x 106 (Z²/n²)
Κ.Εn =
2.18 x 10-¹⁸ (Z²/n²)
P.En =
4.36 x 10-¹⁸ (Z²/n²)
Frequency(vn) =
(Wave number)n =
Time taken to complete one revolution is proportional to which powers of n & Z?
Total number of spectral lines obtained in H atom (when electron jump from n2 to n1) equal to -
The Bohr model could not explain the ability of atoms to form molecules by chemical bonds T/F
Splitting of spectral lines in the presence of magnetic field is called -
Splitting of spectral lines in the presence of electric field is called -
Bohr was able to explain the occurrence of Zeeman and Stark effect T/F
Describe Heisenberg’s Uncertainty Principle and write its equation (JEE)
It states that it is impossible to determine simultaneously, the exact position and exact momentum (or velocity) of or an electron
∆x ∆px greater or equal to h/4π
or
∆x ∆vx greater or equal to h/4πm
When an electron is in any energy state, the wave function corresponding to that energy state contains all information about the electron. T/F
T
The energy of electrons in atoms is not quantized. T/F
F
The number which identifies the shell is -
Principal quantum number
Azimuthal quantum number is also called _______ or _______
orbital angular momentum or subsidiary quantum number
________ identifies the three dimensional shape of the Orbital
Azimuthal quantum number
For n = 3, tell the possible values of I (JEE)
l = 0, 1, 2
For any subshell I ______ values of m are possible (NEET 2023)
2l +l
________ number refers to the orientation of spin of electrons.
Spin quantum number
Spin angular momentum of the electron is a vector quantity. T/F
T
_______ gives information about the spatial orientation of the orbital with respect to standard set of co- ordinate axis. (NEET)
Magnetic orbital quantum number
For I = 2, m can be -
+2, +1, 0, -1, -2
Subsidiary quantum number also determine the energy of the orbital to some extent. T/F
T
What is the total no. of orbitals associated with n = 3?
Total no. of orbitals = n². Hence 3² = 9
A 4s orbital have ________ number of nodes
3
Boundary surface diagrams enclose the area where probability of finding electrons is _______
90%
Electron is located further away from the nucleus as the principal quantum number increases T/F
T
There is no simple relation between the values of m (-I, 0 and +I) and the x y and z directions. T/F
T
Maximum no of electrons in a subshell I = (NEET)
4l + 2
Total no. of nodes =
n-l
Angular nodes =
I (azimuthal quantum number)
Radial nodes =
n- I (azimuthal quantum number) - 1
What are angular nodes?
Nodal planes passing through origin which have zero probability of electrons
Angular momentum of the electron in an orbital - (NEET)
(h/2π) √l[(l + l)]
Angular momentum of the electron in an orbital - (NEET)
(h/2π) √[s(s + l)]
Spin multiplicity-
2s + 1
No. of sub shells in nth shells-
n
No. of orbitals in nth shell-
n²
What is the main reason for having different energies of the subshells in multi-electron species?
Mutual repulsion among the electrons
In general, the repulsive interaction of the electrons in the outer shell with the electrons in the inner shell are more important. T/F
T
Despite the shielding of the outer electrons from the nucleus by the inner shell electrons, the attractive force experienced by the outer shell electrons increases with increase of nuclear charge. T/F
T
p-orbital electron spends more time close to the nucleus in comparison to s orbital T/F
F
The Zeff experienced by the electron increases with increase of azimuthal quantum number (D. T/F
F
If two orbitals have same value of (n + 1), then how will we decide when one is lower in energy?
The one with lower value of n will have lower energy
Energies of the orbitals in the same subshell decrease with increase in the atomic number (Zeff). T/F
T
In the H atom, 4s have less energy than 3d. T/F
F
Energy of 2s orbital of hydrogen atom is greater than that of 2s orbital of lithium. T/F
T
Aufbau principle is based on - (3)
Pauli’s exclusion principle, the Hund’s rule of maximum multiplicity and the relative energies of the orbitals
Write order of filling orbitals till Is orbital.
Is, 2s 2p 3 s, 3p 4s, 3d, 4p, 5s 4d, 5p 6s, 4f, 5d, 6p, 7s
[Trick - Remember this sequence - S SP SP SDP SDP SFDP SFDP {which implies - Is (S) 2s 2p (SP) 3s 3p (SP) 4s 3d 4p (SDP)…) Using this, you will not have to make that hard diagram of Order of filling every time]
What is Pauli Exclusion Principle? (NEET)
No two electrons in an atom can have the same set of four quantum numbers
The maximum number of electrons in the shell with principal quantum number n is equal to -
2n²
What is Hund’s Rule?
pairing of electrons in the orbitals belonging to the same subshell (p, d or f) does not take place until each orbital belonging to that subshell has got one electron each i.e., it is singly occupied
What are valence electrons ?
electrons that are added to the electronic shell with the highest principal quantum number are called valence electrons
Write electronic configuration of Cr
[Ar] 3d⁵ 4s¹
Write electronic configuration of Cu
[Ar] 3d¹⁰ 4s¹
Fully filled orbitals and half filled orbitals have extra stability. T/F
T
Causes of stability of completely filled and half filled subshells are - (2)
Causes of stability of completely filled and half filled subshells are
(i) Symmetrical distribution of electrons
(ii) exchange energy
Atoms of all elements are composed of two fundamental particles. T/F (NEET 2023)
T
Protons and electrons are collectively known as nucleons. (NEET 2023)
F, Protons and neutron are collectively known as nucleons
DigaQ. I
A-Is
B-2s
DigaQ. 2. This is the boundary surface diagram of - (NEET 2022)
DigaQ. 2- Boundary surface diagrams of 3d orbitals
A-d(yz)
B-d(x²-y²)
C-d(z²)
