Chemistry Formulas for Atomic Structure
Chemistry Formulas from Bohr’s Model
of Atom
·
Angular
momentum of electron in n^{th} orbit
Where, m = Mass of the electron,
v = velocity
of electron,
r = radius
of the orbit,
h = Planck’s
constant,
n = no. of
orbit in which electron is present,
·
Energy
of electron in n^{th} orbit
Where, Z = Atomic No. of Electron,
·
Energy
absorbed or released in an electron jump (
E)
·
Radius
of orbits of hydrogen like species
For hydrogen atom Z = 1, for first orbit n = 1,
On substituting values of the constants
h = 6.62x10^{27}erg sec,
m = 9.1x10^{28}g,
e = 4.8x10^{10}
we get,
r = 0.529 Å
So, radius of first orbit of
hydrogen atom is 0.529 Å.
·
Radius
of n^{th} orbits of hydrogen like species
r_{n} = 0.529n^{2}/Z Å
·
Velocity
of electron in n^{th} orbit
On substituting values of the constants
We get,
·
No.
of revolution per second made by an electron around the nucleus of atom
·
Energy
of electron in n^{th} orbit (E_{n})
On substituting values of the constants
We get,
In general,
·
Energy
of electron in a Hydrogen Atom in different energy levels
Energy
Level

E
(Joules/atom)

E
(eV/atom)

E
(kcal/mol)

1

21.79x10^{19}

13.6

313.5

2

5.42x10^{19}

3.4

78.4

3

2.41x10^{19}

1.51

38.84

4

1.36x10^{19}

0.85

19.6

5

0.87x10^{19}

0.544

12.5

Infinite

0

0

0

·
Frequency
or wave length of emitted radiation
Where, λ = wavelength of emitted radiations
R = Rydberg constant for Hydrogen atom
·
Number
of spectral lines produced when an electron drops from n^{th} level to
ground level
Chemistry Formulas from Photoelectric
Effect
·
Planck’s
Relationship,
E = hv
·
Total
energy,
Total Energy = (mv^{2}/2)
+ w
Where,
w = energy required to remove the electron.
Chemistry Formulas from Wave
Mechanical Concept of Atom
·
De
Broglie’s Equation,
Where, m = mass of particle,
v = velocity of the particle,
h = Planck’s Constant,
or,
Chemistry Formulas from Heisenberg’s
Uncertainty Principle
·
Heisenberg’s
Uncertainty Principle,
Where,
= uncertainty in the position of the particle,
= uncertainty in the momentum of the particle,
Also,
Chemistry Formulas from Quantum
Numbers
·
Principle
Quantum Number (n),
Maximum no. of electrons in n principle quantum number = 2n^{2}
·
Azimuthal
Quantum Number (l),
For the given value of principle quantum number (n), azimuthal quantum number (l), may have all integral values from 0 to (n1)
·
Magnetic
Quantum Number (m),
No.
of orbitals in a subshell = 2 l
+1
·
Spin
Quantum Number (s),
For
spinning of electron about its own axis