What are the different ways to represent a molecule?

The common representations are the molecular formula (CH₄), the Lewis electron-dot structure, the complete structural (dash) formula, the wedge-dash formula for 3D on paper, and 3D molecular models: framework, ball-and-stick and space-filling. For bonding, an orbital overlap diagram shows which orbitals form each bond.

What does a wedge and a hashed wedge mean in a wedge-dash formula?

A plain line is a bond in the plane of the paper. A solid wedge is a bond coming out of the paper towards the viewer, and a hashed (dashed) wedge is a bond going behind the paper, away from the viewer. The narrow end of the wedge is at the atom the bond starts from.

What is the difference between ball-and-stick and space-filling models?

A ball-and-stick model shows atoms as balls and bonds as sticks, so the bond angles and connectivity are easy to see. A space-filling model draws each atom at its van der Waals radius, so the atoms overlap and the model shows the molecule's real size and outer shape, but the bonds and angles are hidden.

Why does the Lewis structure of CH₄ look square when methane is tetrahedral?

A Lewis structure is drawn flat on paper and only shows which electron pairs are shared. The 90° angles in the drawing are not real. In the actual molecule the four C–H bonds point to the corners of a tetrahedron, 109°28′ apart.

What orbitals overlap to form the C–H bonds in methane?

Carbon's 2s and three 2p orbitals mix to give four sp³ hybrid orbitals, each with one electron. Each sp³ orbital overlaps head-on with the 1s orbital of one hydrogen to form a σ(sp³–1s) bond, so all four C–H bonds in methane are identical.

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Types of Representation

PhysicalEasyNEET: 3-4 Q3D

Chemistry lab

Different Types of Representation of a Molecule

Chemical Bonding & Molecular Structure

Explore the interactive model.

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Next → to step through the 7 models · drag to rotate any view

How to use this lab

1Next → dabao — wahi CH₄ 7 tarah se draw hota hai: Lewis se orbital overlap tak.
2Stop 2 → 3 pe dekho: flat paper wala plus sign 3D tetrahedron ban jaata hai.
3Har stop pe niche padho: yeh model kya dikhata hai, kya chhupata hai. Stop 3 se drag karke ghumao.

About this lab

One molecule, seven drawings: step methane from its Lewis structure through structural formula, wedge-dash, framework, ball-and-stick and space-filling models to the sp³–1s orbital overlap picture.

What you're seeing

Every representation of a molecule shows some things and hides others. A Lewis structure shows the shared electron pairs but not the shape; a wedge-dash formula puts the 3D shape on paper; a space-filling model shows the real size but hides the bonds. NEET asks you to read all of them, so this lab draws the same CH₄ molecule seven ways.