Answer:
Enantiomers/ Isomers/ Stereoisomers/ Meso compounds/ Constitutional isomers/ Diastereomers.
Explanation:
Isomers are molecules that have the same chemical formula but have different conformation, or in its connections, or the orientation in space. Isomers have different chemical and physical properties (second blank).
The isomers that only differ by the orientation of their atoms in space are called stereoisomers (third blank).
The stereoisomers that have a chiral carbon and do not mirror images of each are called enantiomers (first blank). They can deviate the polarized light.
When a compound has two or more chiral carbons but they compensate for the deviation of the light, and the compound is optically inactive, it's called a meso compound (fourth blank).
When the isomers differ in the way the atoms are connected it's called a constitutional isomer (fifth blank).
When the molecule has more than one chiral carbon, it will have pairs of enantiomers. The isomers that aren't of the same pair are nonsuperimposable mirror images of each other and are called diastereomers (last blank).
Mass is the amount of matter in an object. Density is the degree of compactness of a substance
The atom contain 6 neutrons, if that's the question
There are four type of intermolecular forces: ionic, dipole-dipole, hydrogen bonds and London disperssion forces.
CH4 have no ions, so there are not ionic forces.
CH4 is a symetrical molecule, so there cannot be a net dipole in the molecule, so there is not dipole-dipole interaction.
Hydrogen bonding is only possbile when H is bonded to N, O or F, beacuse they are the atoms that considerable higher electgronegativy than hydrogen.
So, the only intermolecular force present in CH4 molecules is London disperssion forces, which is a force present in any molecule and is the weakiest one. That explains the low melting and boiling points of CH4.