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 = 6.62×10^{27}erg sec,
m = 9.1×10^{28}g,
e = 4.8×10^{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

21.79×10^{19}

13.6

313.5

2

5.42×10^{19}

3.4

78.4

3

2.41×10^{19}

1.51

38.84

4

1.36×10^{19}

0.85

19.6

5

0.87×10^{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