How to judge whether alkanes have plane structure or three-dimensional structure

For simple organic matter, it can be judged that if each carbon atom has three or two atoms, it may be a * * * surface; If a carbon atom is combined with four atoms, at most two of the four atoms combined with this carbon atom can be in the plane of the carbon atom.

Second, the nature of alkanes:

At room temperature, alkanes containing 1 ~ 4 carbon atoms are gases; At room temperature, alkanes containing 5 ~ 8 carbon atoms are liquid; Alkanes containing 8 ~ 16 carbon atoms can be solid or liquid; N-alkanes with more than 17 carbon atoms are solid, but the melting point (melting point 99℃) of n-alkanes with 60 carbon atoms does not exceed 100℃. Low boiling point alkanes are colorless liquids with special odor. High boiling point alkanes are viscous oily liquids and tasteless. Alkane is a nonpolar molecule with zero dipole moment, but the charge distribution in the molecule is not very uniform, and it can produce instantaneous dipole moment in motion, and there is interaction force (dispersion force) between the instantaneous dipole moments. In addition, there are van der Waals forces between molecules, which are one or two orders of magnitude smaller than chemical bonds, and the energy required to overcome these forces is also low, so the melting point and boiling point of general organic substances rarely exceed 300℃.