Chemistry · Inorganic Chemistry

Classification of Elements and Periodicity in Properties formulas for JEE

Every Classification of Elements and Periodicity in Properties formula you need for JEE, grouped by concept.

FormulasRevision notes
12 formulas2 concepts
01Modern Periodic Table and Law02Periodic Trends in Properties
01

Modern Periodic Table and Law

1 formula

Moseley's Law

ν=a(Z−b)\sqrt{\nu} = a(Z - b)

Relates the frequency of emitted X-rays to the atomic number of an element.

applies whenaa is a proportionality constant and bb is a screening constant.
moseleyx-rayjee-advanced
02

Periodic Trends in Properties

11 formulas

Acidic Oxide Reaction with Water

Cl2O7+H2O→2HClO4Cl_2O_7 + H_2O \rightarrow 2HClO_4

Demonstrates the highly acidic nature of extreme right-side non-metallic oxides.

applies whenStandard test reaction for Group 17 non-metal oxides.
oxideacidicreactionworked-example

Allred-Rochow Electronegativity

χAR=0.359Zeffr2+0.744\chi_{AR} = 0.359 \frac{Z_{eff}}{r^2} + 0.744

Electronegativity based on the electrostatic force exerted by the effective nuclear charge on valence electrons.

applies whenrr is the covalent radius in Angstroms (A˚\text{\AA}).
electronegativityallred-rochowjee-advanced

Basic Oxide Reaction with Water

Na2O+H2O→2NaOHNa_2O + H_2O \rightarrow 2NaOH

Demonstrates the highly basic nature of extreme left-side metallic oxides.

applies whenStandard test reaction for Group 1 metal oxides.
oxidebasicreactionworked-example

Thermodynamic Electron Affinity Relation

ΔegH=−Ae−52RT\Delta_{eg}H = -A_e - \frac{5}{2}RT

Relationship between electron gain enthalpy and electron affinity at a given temperature.

applies whenAssumes ideal gas behavior for the added electron; TT is temperature.
electron-affinitythermodynamics

Electron Gain Enthalpy

X(g)+e−→X−(g)X(g) + e^- \rightarrow X^-(g)

Reaction and enthalpy change when an electron is added to a neutral gaseous atom.

applies whenIsolated gaseous atom.
electron-gainenthalpy

First Ionization Enthalpy

X(g)→X+(g)+e−X(g) \rightarrow X^+(g) + e^-

Reaction and enthalpy change for removing the first electron from an isolated gaseous atom.

applies whenIsolated gaseous atom in its ground state.
ionizationenthalpyfirst

Second Ionization Enthalpy

X+(g)→X2+(g)+e−X^+(g) \rightarrow X^{2+}(g) + e^-

Reaction and enthalpy change for removing the second most loosely bound electron.

applies whenPositive isolated gaseous ion.
ionizationenthalpysecond

Ionization Enthalpy of Hydrogen

ΔiH=(E∞−E1)×NA=2.18×10−18NA J/mol\Delta_iH = (E_{\infty} - E_1) \times N_A = 2.18 \times 10^{-18} N_A \text{ J/mol}

Calculation of the ionization enthalpy of 1 mole of atomic hydrogen from its ground state energy.

applies whenDerived from E1=−2.18×10−18 JE_1 = -2.18 \times 10^{-18}\text{ J}.
ionizationhydrogenexercise

Mulliken Electronegativity

χM=IE+EA2\chi_M = \frac{IE + EA}{2}

Electronegativity based on the arithmetic mean of ionization energy and electron affinity.

applies whenIE and EA are in electron-volts (eV) per atom.
electronegativitymullikenjee-advanced

Pauling Electronegativity Difference

∣χA−χB∣=0.208ΔA−B|\chi_A - \chi_B| = 0.208 \sqrt{\Delta_{A-B}}

Calculates the difference in electronegativity between two bonded atoms using bond dissociation energies.

applies whenΔA−B=EA−B−EA−AEB−B\Delta_{A-B} = E_{A-B} - \sqrt{E_{A-A} E_{B-B}}. Energies are in kcal/mol.
electronegativitypaulingjee-advanced

Effective Nuclear Charge

Zeff=Z−σZ_{eff} = Z - \sigma

Net positive charge experienced by an electron in a multi-electron atom.

applies whenσ\sigma is the shielding or screening constant calculated via Slater's rules.
slatereffective-chargejee-advanced
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