NEET Chemistry tricks for Organic and Inorganic

Shortcuts that save time in NEET Chemistry, from redox and periodic exceptions to hybridisation and Organic directing groups, with the conditions where each one applies.

Paper Predict Notes · 10 Feb 2026

Chemistry tricks are worth learning when they save time without causing errors. The ones below are reliable for NCERT-level questions, as long as you know when they apply. Each comes with the condition you need to check before using it.

Redox

OIL RIG

Oxidation Is Loss, Reduction Is Gain of electrons. A Hinglish version some students prefer is "LEO bole GER": Loss of Electrons is Oxidation, Gain of Electrons is Reduction.

Oxidation number shortcut

An increase in oxidation number means oxidation. A decrease means reduction. The species that is oxidised is the reducing agent, and the one reduced is the oxidising agent.

Periodic trends and their exceptions

General trends across a period, left to right:

• Atomic radius decreases.
• Ionisation enthalpy generally increases.
• Electronegativity increases.

Down a group, atomic radius increases and ionisation enthalpy decreases.

The exceptions are what questions test most often.

• Ionisation enthalpy of N is higher than O. Nitrogen has a stable half-filled 2p subshell.
• Ionisation enthalpy of Be is higher than B. Removing an electron from boron's 2p is easier than from beryllium's filled 2s.
• Electron gain enthalpy of Cl is more negative than F. Fluorine is very small, so the added electron faces strong repulsion.

Hybridisation formula

For many simple molecules and ions, you can find the hybridisation of the central atom with:

H = ½ (V + M − C + A)

• V = valence electrons of the central atom
• M = number of monovalent atoms attached (such as H or halogens)
• C = charge of a cation
• A = charge of an anion

Then: H = 2 means sp, 3 means sp², 4 means sp³, 5 means sp³d, 6 means sp³d².

Example: in NH₄⁺, V = 5, M = 4, C = 1, so H = ½(5 + 4 − 1) = 4, giving sp³.

Check the shape separately using lone pairs. Hybridisation and shape are related but not the same, for example NH₃ is sp³ but pyramidal.

Organic Chemistry

Ortho-para and meta directing groups

In electrophilic substitution on benzene:

• Ortho-para directors (activating): −OH, −NH₂, −OR, −CH₃ and other alkyl groups.
• Ortho-para directors (deactivating): halogens. They slow the reaction but still direct to ortho and para positions.
• Meta directors (deactivating): −NO₂, −CN, −CHO, −COOH, −COR.

A quick check: groups with a lone pair on the atom attached to the ring usually direct ortho-para. Groups with a multiple bond to an electronegative atom usually direct meta.

SN1 vs SN2

• SN1: favoured by tertiary substrates and polar protic solvents. It goes through a carbocation, so rearrangements and racemisation are possible.
• SN2: favoured by primary substrates, strong nucleophiles and polar aprotic solvents. It happens in one step with inversion of configuration.

Carbocation stability

Tertiary is more stable than secondary, which is more stable than primary, which is more stable than methyl. Resonance-stabilised carbocations, such as benzyl and allyl, are especially stable.

Acidity comparisons

Electron-withdrawing groups increase acidity; electron-donating groups decrease it. That is why phenol is more acidic than alcohols, and why nitrophenols are more acidic than phenol.

Coordination compounds

Naming order

Ligands are named in alphabetical order before the metal. Anionic ligands end in "o" (chlorido, cyanido). If the complex ion is an anion, the metal name ends in "-ate".

When not to use a trick

• When the question is about an exception the trick does not cover.
• When you are unsure whether the condition applies.
• When a full method is quick anyway.

Tricks should speed up what you already understand. They are not a replacement for the concept.

Frequently asked questions

Do tricks work for all NEET Chemistry questions?

No. They help with specific types, such as hybridisation, trends and directing groups. Many questions still need full understanding.

Is the hybridisation formula always correct?

It works well for common molecules and ions at NCERT level. For complex cases, use VSEPR reasoning.

Where are these tricks in the notes?

Paper Predict Notes place tricks and mnemonics beside the topics they apply to, along with PYQs.

The short version

Learn a few reliable tricks: OIL RIG for redox, the periodic exceptions for N, Be and Cl, the hybridisation formula, ortho-para versus meta directors, and SN1 versus SN2 conditions. Always check the condition before using a shortcut.

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