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Periodic Table & Periodicity formula sheet

Every formula in the Periodic Table & Periodicity chapter for JEE Main, with one line on when it applies. Topic 1 is open to everyone; sign in free to read all 18 and download the PDF.

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Periodic law and the modern table

Moseley's law
4× asked, last 2025
ν=a (Z−b)\sqrt\nu=a\,(Z-b)
ν\nu: X-ray frequency. Atomic number, not mass, orders the table. Mendeleev predicted eka-aluminium (Ga), eka-silicon (Ge).
Periods and blocks
4× asked, last 2025
elements per period=2×orbitals filled2, 8, 8, 18, 18, 32, 32\begin{aligned}&\text{elements per period}=2\times\text{orbitals filled}\\&2,\ 8,\ 8,\ 18,\ 18,\ 32,\ 32\end{aligned}
Period = valence nn. s (groups 1–2), p (13–18), d (3–12), f (ZZ 58–71, 90–103). He sits in group 18.
Group from configuration
5× asked, last 2025
group={nss-blockns+ndd-block10+ns+npp-block\text{group}=\begin{cases}n_s&\text{s-block}\\ n_s+n_d&\text{d-block}\\ 10+n_s+n_p&\text{p-block}\end{cases}
Count from the noble gas below ZZ (2, 10, 18, 36, 54, 86). Z=26Z=26: 3d64s23d^64s^2, period 4, group 8.
IUPAC names for Z > 100
3× asked, last 2025
0 nil, 1 un, 2 bi, 3 tri, 4 quad5 pent, 6 hex, 7 sept, 8 oct, 9 enn\begin{aligned}&0\ \text{nil},\ 1\ \text{un},\ 2\ \text{bi},\ 3\ \text{tri},\ 4\ \text{quad}\\&5\ \text{pent},\ 6\ \text{hex},\ 7\ \text{sept},\ 8\ \text{oct},\ 9\ \text{enn}\end{aligned}
Roots + -ium; symbol = initials: 120 unbinilium (Ubn). For ZZ = 104–118, group =Z−100=Z-100.

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14 more formulas in 5 topics

Atomic and ionic radii; Ionisation enthalpy; Electron gain enthalpy; Electronegativity, metallic character and oxides; and Valence and diagonal relationship. Read the first part free. Sign in free with Google to read the rest and download the PDF.

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Atomic and ionic radii

  • Atomic radius (pm)14×
  • Ions versus atoms7×
  • Isoelectronic species14×

Ionisation enthalpy

  • Ionisation enthalpy5×
  • IE across a period (kJ mol⁻¹)22×
  • IE down groups 13 and 149×
  • Successive IEs9×

Electron gain enthalpy

  • Electron gain enthalpy11×
  • Cl beats F, S beats O14×

Electronegativity, metallic character and oxides

  • Electronegativity (Pauling)11×
  • Metallic character18×
  • Nature of oxides12×

Valence and diagonal relationship

  • Valence4×
  • Diagonal relationship5×

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