TS Inter 1st Year Chemistry Notes Chapter 1 Atomic Structure

Here students can locate TS Inter 1st Year Chemistry Notes 1st Lesson Atomic Structure to prepare for their exam.

TS Inter 1st Year Chemistry Notes 1st Lesson Atomic Structure

→ The radiation which is made up of electrical and magnetic fields acting mutually perpendicular to each other is called Electro-magnetic radiation.

→ The number of waves that pass a point in the path of propagation of wave per second is called frequency. It is denoted by υ.

→ The number of waves present in a distance of 1 cm is called wave number. It is the reciprocal of wavelength (i.e.,) υ̅ = 1/λ.

→ According to Planck’s quantum theory emission or absorption of energy takes place in the form of small packets called Quanta. The energy of each quantum of radiation is given by E = hυ.

→ According to Einstein, both emission and absorption of radiation takes place in the form of photons. A photon is a wave particle which has no mass but has energy. The energy of a photon is given by E = hυ.

→ The emission spectrum of hydrogen consists of Lyman series, Balmer series, Paschen series, Bracket series and Pfund series.

→ According to Bohr, electrons revolve around the nucleus in certain definite circular paths, called orbits or energy levels or shells. They are denoted by the letter n.

→ Principal quantum number describes the size of the orbit and energy of the electron.

→ Azimuthal quantum number denotes the shape of the orbital.

→ Magnetic quantum number denotes the special orientation of the orbital.

→ Spin quantum number describes the direction of rotation of the revolving electron.
Its value is + 1/2 for a clockwise electron and – 1/2 for an electron revolving in the anti-clockwise direction.

→ Wave nature of electron was proposed by de Broglie.

TS Inter 1st Year Chemistry Notes Chapter 1 Atomic Structure

→ According to Heisenberg’s uncertainty principle, it is not possible to determine the position and the velocity of a moving particle like electron, simultaneously and accurately.

→ Ψ is known as wave function and Ψ2 is known as probability function.

→ Orbital is the space around the nucleus where the probability of finding the electron is maximum.

→ Orbitals of equal energy are called degenerate orbitals.

→ Arrangement of electrons in space around the nucleus in an atom is known as electronic configuration.

→ According to Pauli’s exclusion principle, an orbital can hold a maximum of two electrons only and a shell can hold a maximum of 2n electrons.

→ Atoms or ions with paired up electron spins * are diamagnetic and with unpaired electron spins are paramagnetic.

→ Atoms or ions with the same electronic configuration are said to be iso-electronic.

→ The wave number u of the spectral lines is given by Rydberg expression,
υ̅ = \(\frac{1}{\lambda}\) = RH\(\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)\)

→ Value of Rydberg constant
(RH) = 109,677 cm-1.

→ Energy of photon, E = hυ.

→ Energy of a photoelectron,
E = hυ = hυ0 + K.E,
where υ0 = threshold frequency.

→ Mass of an electron, m = 9.1 × 10-28 g.

→ Charge of an electron, e =-4.802 × 10-10 e.s.u.

→ Radius of nth orbit
(rn) = 0.529 × 10-8 n2cm.

→ Radius of Bohr’s orbit
(r) = 0.529 × 10-8 cm = 0.529 Å.

TS Inter 1st Year Chemistry Notes Chapter 1 Atomic Structure

→ Energy of electron in the nth orbit,
(En) = \(-\frac{13.6}{n^2}\)eV

→ Value of Rydberg constant (R) = \(\frac{2 \pi^2 \mathrm{me}^4}{\mathrm{ch}^3}\)

→ de Broglie wavelength, λ = \(\frac{\mathrm{h}}{\mathrm{mV}}\).

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