molecule
Chemistry term for a molecule, often used with substance names such as 水の分子 or in compounds such as 分子構造.
A water molecule is made of two hydrogen atoms and one oxygen atom.
numerator
Mathematical term for the number or expression above the line in a fraction; contrasted with 分母.
In two thirds, two is the numerator and three is the denominator.
element of a group; member
Used for a person or element within a group, especially in set phrases or evaluative compounds such as 不穏分子 or 危険分子. It is not the ordinary everyday word for a group member.
The police were watching out for subversive elements within the organization.
Rare or limited use meaning a small particle; do not confuse this with the grammar term 助詞. In ordinary modern technical contexts, 粒子 is usually clearer unless 分子 specifically means molecule.
See also: 微分子
Depending on the context, 分子 can refer to a small particle.
A water molecule is made up of one oxygen atom and two hydrogen atoms.
If you swap the numerator and denominator of a fraction, you get its reciprocal.
It seems there are dangerous elements mixed in among the organization.
molecular beam
molecular theory