KEY CONCEPT STRUCTURE OF ATOM Rutherford's Model Bohr's Model Wave mechanical model EXTRA NUCLEAR PART (e− ) Electrons,protons & neutrons are the most important fundamental particles of atoms of all elements (Except hydrogen) Some uncommon Fundamental particles : 1. XA , A = Z + n Z 1 1 1 mM = + = m = mass of e– ; M = Mass of nucleus µ M m m+M
2.
Reduced mass
3.
Photon is considered massless bundle of energy. But to find its mass use m =
4.
E = mc2 , E = hν = hc/ λ = hc ν
5.
Quantum efficiency or Quantum Yield =
6.
Rn = R1 (A)1/3 , R1 = 1.33 ×10–13 cm
7.
no. of molecules reacting no. of quanta absorbed A = mass number
θ 1 1 Z . 2e m α v α2 = K e ; Tan α 2 b 2 r 1 number of a particles at θ = K 4 ; sin θ / 2 1
1
h λc
b = impact parameter
1 2 ×Z 2 2 n1 n 2
=ν=R H
−
8.
Rydberg’s Equation λ
9. 10.
Limiting spectral line (series limit) means n2 = ∞ Hα line means we know n1 , n2 (longest λ , shortest ν , least E) [ Hα , Hβ , Hγ , Hδ ] n (n − 1) No. of wavelengths observed in the spectrum = 2 when e– deexcites to ground state , n = no. of higher orbit
11. 12.
1/2 mv2 = hν – hν 0(w) (work function or B.E.) hc ν 0 = Threshhold frequency W = hν 0 = λ 0
13.
Accelerating potential = eV = KE =
14.
λ = hc/E = 1240 ev. nm
15.
K=
1
4πε
; P.E. = 0
16.
mvr = n·
17.
En =
1 2 mv 2
K q1 q 2 centrifugal force = mv2/r r
h = n . 2π
E1 2 z 2 n
=–
2 4 2π 2 me 4 2 − 2π me z ; E = 1 2 n2h2 h
3