Which chapter are directly on reading and formula based topics and have weightage for jee mains 2018? Plz tell me

In chemistry direct questions come from ncert.

Coordinate gemotery and , 3d, vector

One can't tell you like that.However below  is the list of some important chapters for your preparation of jee mains 2018:
Important Topics For JEE Main 2018

Listed below are the important topics for JEE Main subject wise based on previous years papers.

Important Topics For JEE Main Chemistry:

p Block Elements
Coordination Compounds
Biomolecules and Polymers
d and f Block elements
Chemical Bonding and Molecular Structure
s Block elements ( Alkali and Alkaline earth Metals) and Hydrogen
Electrochemistry
Chemical Kinetics
Atomic Structure
Alkanes, Alkenes and Alkynes ( Hydrocarbons)
Important Topics For JEE Main Physics:

Properties of Matter and Fluid Mechanics
Electrostatics
Semiconductors and Communication System
Electromagnetic Induction and Alternating Current
Ray Optics
Magnetic Effects of Current
Laws of Thermodynamics
Current Electricity
Atomic Structure in Modern Physics
Important Topics For JEE Main Maths:

Trigonometrical Ratios, Functions and Identities
Sequences and Series (Progressions)
Vector
Permutation and Combination
Statistics
Parabola
Definite Integration
Circle
Indefinite Integration
Binomial Theorem
Quadratic Equations