Cheat Sheet: Atomic Structure | Chemistry Class 11 - NEET PDF Download

 Page 1


Atomic Structure Cheat Sheet  
(EduRev) 
Rutherford’s Nuclear Model 
Key Concepts 
? Experiment: a-particles bombarded thin (10
-4
 mm) Au foil. 
? Nucleus: Small, heavy, positively charged, contains protons and neutrons 
(nucleons). 
? Properties: Central, discovered 1911, holds most mass. 
? Drawbacks: Cannot explain electron stability, discontinuous spectrum, line 
spectra. 
Planck’s Quantum Theory 
Key Concepts 
? Energy Quanta: E = h ?, ? = c/?, so E = hc/ ?. 
? Planck’s Constant: h = 6.626 × 10
-34
 Js = 6.626 × 10
-27
 erg s. 
Photoelectric Effect 
Key Concepts 
? Einstein’s Equation: ½mv
max
2
 = h? - h?
0
 = hc(1/? - 1/ ?
0
). 
Page 2


Atomic Structure Cheat Sheet  
(EduRev) 
Rutherford’s Nuclear Model 
Key Concepts 
? Experiment: a-particles bombarded thin (10
-4
 mm) Au foil. 
? Nucleus: Small, heavy, positively charged, contains protons and neutrons 
(nucleons). 
? Properties: Central, discovered 1911, holds most mass. 
? Drawbacks: Cannot explain electron stability, discontinuous spectrum, line 
spectra. 
Planck’s Quantum Theory 
Key Concepts 
? Energy Quanta: E = h ?, ? = c/?, so E = hc/ ?. 
? Planck’s Constant: h = 6.626 × 10
-34
 Js = 6.626 × 10
-27
 erg s. 
Photoelectric Effect 
Key Concepts 
? Einstein’s Equation: ½mv
max
2
 = h? - h?
0
 = hc(1/? - 1/ ?
0
). 
? Terms: ?
0
, ?
0
 are threshold frequency and wavelength. 
Bohr’s Atomic Model 
Postulates 
? Positively charged nucleus. 
? Electrons in circular orbits. 
? Angular momentum: L = mvr = nh/(2p), n = 1, 2, 3, …. 
? No energy loss in permitted orbits. 
Advantages 
? Explains spectra of one-electron species (H, He
+
, Li
2+
). 
Spectral Series 
Key Series 
Series Region Transition 
Lyman Ultraviolet n
1
 = 1, n
2
 = 2, 3, … 
Balmer Visible n
1
 = 2, n
2
 = 3, 4, … 
Paschen Infrared n
1
 = 3, n
2
 = 4, 5, … 
Brackett Infrared n
1
 = 4, n
2
 = 5, 6, … 
Page 3


Atomic Structure Cheat Sheet  
(EduRev) 
Rutherford’s Nuclear Model 
Key Concepts 
? Experiment: a-particles bombarded thin (10
-4
 mm) Au foil. 
? Nucleus: Small, heavy, positively charged, contains protons and neutrons 
(nucleons). 
? Properties: Central, discovered 1911, holds most mass. 
? Drawbacks: Cannot explain electron stability, discontinuous spectrum, line 
spectra. 
Planck’s Quantum Theory 
Key Concepts 
? Energy Quanta: E = h ?, ? = c/?, so E = hc/ ?. 
? Planck’s Constant: h = 6.626 × 10
-34
 Js = 6.626 × 10
-27
 erg s. 
Photoelectric Effect 
Key Concepts 
? Einstein’s Equation: ½mv
max
2
 = h? - h?
0
 = hc(1/? - 1/ ?
0
). 
? Terms: ?
0
, ?
0
 are threshold frequency and wavelength. 
Bohr’s Atomic Model 
Postulates 
? Positively charged nucleus. 
? Electrons in circular orbits. 
? Angular momentum: L = mvr = nh/(2p), n = 1, 2, 3, …. 
? No energy loss in permitted orbits. 
Advantages 
? Explains spectra of one-electron species (H, He
+
, Li
2+
). 
Spectral Series 
Key Series 
Series Region Transition 
Lyman Ultraviolet n
1
 = 1, n
2
 = 2, 3, … 
Balmer Visible n
1
 = 2, n
2
 = 3, 4, … 
Paschen Infrared n
1
 = 3, n
2
 = 4, 5, … 
Brackett Infrared n
1
 = 4, n
2
 = 5, 6, … 
Series Region Transition 
Pfund Infrared n
1
 = 5, n
2
 = 6, 7, … 
Dual Nature of Electron 
Key Concepts 
? De Broglie Relation: ? = h/(mv) = h/p. 
? Derived from E = h ? = mc
2
. 
Heisenberg’s Uncertainty Principle 
Key Concepts 
? Position-Momentum: ?x · ?p = h/(4p), or ?x · ?v = h/(4pm). 
? Energy-Time: ?E · ?t = h/(4p). 
Schrödinger Wave Equation 
Key Concepts 
? Equation: ?
2
?/?x
2
 + ?
2
?/?y
2
 + ?
2
?/?z
2
 + (8p
2
m/h
2
)(E - V)? = 0. 
? Purpose: Finds probability via wave function ?. 
Quantum Numbers 
Types 
? Principal (n): Energy, size (n = 1, 2, 3, …). 
Page 4


Atomic Structure Cheat Sheet  
(EduRev) 
Rutherford’s Nuclear Model 
Key Concepts 
? Experiment: a-particles bombarded thin (10
-4
 mm) Au foil. 
? Nucleus: Small, heavy, positively charged, contains protons and neutrons 
(nucleons). 
? Properties: Central, discovered 1911, holds most mass. 
? Drawbacks: Cannot explain electron stability, discontinuous spectrum, line 
spectra. 
Planck’s Quantum Theory 
Key Concepts 
? Energy Quanta: E = h ?, ? = c/?, so E = hc/ ?. 
? Planck’s Constant: h = 6.626 × 10
-34
 Js = 6.626 × 10
-27
 erg s. 
Photoelectric Effect 
Key Concepts 
? Einstein’s Equation: ½mv
max
2
 = h? - h?
0
 = hc(1/? - 1/ ?
0
). 
? Terms: ?
0
, ?
0
 are threshold frequency and wavelength. 
Bohr’s Atomic Model 
Postulates 
? Positively charged nucleus. 
? Electrons in circular orbits. 
? Angular momentum: L = mvr = nh/(2p), n = 1, 2, 3, …. 
? No energy loss in permitted orbits. 
Advantages 
? Explains spectra of one-electron species (H, He
+
, Li
2+
). 
Spectral Series 
Key Series 
Series Region Transition 
Lyman Ultraviolet n
1
 = 1, n
2
 = 2, 3, … 
Balmer Visible n
1
 = 2, n
2
 = 3, 4, … 
Paschen Infrared n
1
 = 3, n
2
 = 4, 5, … 
Brackett Infrared n
1
 = 4, n
2
 = 5, 6, … 
Series Region Transition 
Pfund Infrared n
1
 = 5, n
2
 = 6, 7, … 
Dual Nature of Electron 
Key Concepts 
? De Broglie Relation: ? = h/(mv) = h/p. 
? Derived from E = h ? = mc
2
. 
Heisenberg’s Uncertainty Principle 
Key Concepts 
? Position-Momentum: ?x · ?p = h/(4p), or ?x · ?v = h/(4pm). 
? Energy-Time: ?E · ?t = h/(4p). 
Schrödinger Wave Equation 
Key Concepts 
? Equation: ?
2
?/?x
2
 + ?
2
?/?y
2
 + ?
2
?/?z
2
 + (8p
2
m/h
2
)(E - V)? = 0. 
? Purpose: Finds probability via wave function ?. 
Quantum Numbers 
Types 
? Principal (n): Energy, size (n = 1, 2, 3, …). 
? Azimuthal (l): Shape, subshell (l = 0 to n-1; s, p, d, f). 
? Magnetic (m): Orientation (m = -l to +l, total 2l+1). 
? Spin (s): Spin (s = +1/2, -1/2). 
Angular Momentum 
? Orbital: (h/(2p)) v(l(l+1)). 
? Spin: (h/(2p)) v(s(s+1)). 
Electron Filling Rules 
Key Rules 
? Aufbau Principle: Fill orbitals by increasing energy (1s < 2s < 2p < 3s < …). 
? (n + l) Rule: Lower n + l; if equal, lower n. 
? Pauli’s Exclusion Principle: No two electrons have identical quantum 
numbers. 
? Hund’s Rule: Maximize unpaired electrons in degenerate orbitals. 
Problem-Solving Tactics 
? Use Bohr’s model for one-electron species calculations. 
? Apply de Broglie relation for particles with known mass and velocity. 
? Check quantum number validity (l = n-1, m = |l|). 
? Use Aufbau and n + l rules for electron configurations. 
? Simplify spectral series problems with Rydberg formula. 
Formula Table 
Page 5


Atomic Structure Cheat Sheet  
(EduRev) 
Rutherford’s Nuclear Model 
Key Concepts 
? Experiment: a-particles bombarded thin (10
-4
 mm) Au foil. 
? Nucleus: Small, heavy, positively charged, contains protons and neutrons 
(nucleons). 
? Properties: Central, discovered 1911, holds most mass. 
? Drawbacks: Cannot explain electron stability, discontinuous spectrum, line 
spectra. 
Planck’s Quantum Theory 
Key Concepts 
? Energy Quanta: E = h ?, ? = c/?, so E = hc/ ?. 
? Planck’s Constant: h = 6.626 × 10
-34
 Js = 6.626 × 10
-27
 erg s. 
Photoelectric Effect 
Key Concepts 
? Einstein’s Equation: ½mv
max
2
 = h? - h?
0
 = hc(1/? - 1/ ?
0
). 
? Terms: ?
0
, ?
0
 are threshold frequency and wavelength. 
Bohr’s Atomic Model 
Postulates 
? Positively charged nucleus. 
? Electrons in circular orbits. 
? Angular momentum: L = mvr = nh/(2p), n = 1, 2, 3, …. 
? No energy loss in permitted orbits. 
Advantages 
? Explains spectra of one-electron species (H, He
+
, Li
2+
). 
Spectral Series 
Key Series 
Series Region Transition 
Lyman Ultraviolet n
1
 = 1, n
2
 = 2, 3, … 
Balmer Visible n
1
 = 2, n
2
 = 3, 4, … 
Paschen Infrared n
1
 = 3, n
2
 = 4, 5, … 
Brackett Infrared n
1
 = 4, n
2
 = 5, 6, … 
Series Region Transition 
Pfund Infrared n
1
 = 5, n
2
 = 6, 7, … 
Dual Nature of Electron 
Key Concepts 
? De Broglie Relation: ? = h/(mv) = h/p. 
? Derived from E = h ? = mc
2
. 
Heisenberg’s Uncertainty Principle 
Key Concepts 
? Position-Momentum: ?x · ?p = h/(4p), or ?x · ?v = h/(4pm). 
? Energy-Time: ?E · ?t = h/(4p). 
Schrödinger Wave Equation 
Key Concepts 
? Equation: ?
2
?/?x
2
 + ?
2
?/?y
2
 + ?
2
?/?z
2
 + (8p
2
m/h
2
)(E - V)? = 0. 
? Purpose: Finds probability via wave function ?. 
Quantum Numbers 
Types 
? Principal (n): Energy, size (n = 1, 2, 3, …). 
? Azimuthal (l): Shape, subshell (l = 0 to n-1; s, p, d, f). 
? Magnetic (m): Orientation (m = -l to +l, total 2l+1). 
? Spin (s): Spin (s = +1/2, -1/2). 
Angular Momentum 
? Orbital: (h/(2p)) v(l(l+1)). 
? Spin: (h/(2p)) v(s(s+1)). 
Electron Filling Rules 
Key Rules 
? Aufbau Principle: Fill orbitals by increasing energy (1s < 2s < 2p < 3s < …). 
? (n + l) Rule: Lower n + l; if equal, lower n. 
? Pauli’s Exclusion Principle: No two electrons have identical quantum 
numbers. 
? Hund’s Rule: Maximize unpaired electrons in degenerate orbitals. 
Problem-Solving Tactics 
? Use Bohr’s model for one-electron species calculations. 
? Apply de Broglie relation for particles with known mass and velocity. 
? Check quantum number validity (l = n-1, m = |l|). 
? Use Aufbau and n + l rules for electron configurations. 
? Simplify spectral series problems with Rydberg formula. 
Formula Table 
Category Formula 
Planck’s Theory E = h ?, E = hc/ ? 
Planck’s Constant h = 6.626 × 10
-34
 Js 
Photoelectric Effect ½mv
max
2
 = h? - h?
0
 = hc(1/? - 1/ ?
0
) 
Bohr: Angular Momentum L = mvr = nh/(2p) 
Bohr: Radius r
n
 = (n
2
/Z) × 0.529 Å 
Bohr: Velocity v
n
 = (2.188 × 10
8
 Z)/n cm/s 
Bohr: Energy E
n
 = -13.6 (Z
2
/n
2
) eV/atom 
Bohr: Energy (kJ/mol) E
n
 = -1312 (Z
2
/n
2
) kJ/mol 
Bohr: Energy Difference ?E = 13.6 Z
2
 (1/n
1
2
 - 1/n
2
2
) eV/atom 
Bohr: Wavelength 1/ ? = R Z
2
 (1/n
1
2
 - 1/n
2
2
) 
Rydberg Constant R = 2p
2
 k
2
 m e
4
/(c h
3
) 
De Broglie ? = h/(mv) = h/p 
Heisenberg: Position-Momentum ?x · ?p = h/(4p)