atom

An atom is a basic unit of matter.


Bachelor of Arts

Bachelor of Arts is a degree program that lasts only 4 years.


electrons

An electron is a subatomic  particle that carries a negative electric charge.


emitted

Emitted is the past tense of to "give off".  Example:  "The garbage pit emitted a bad smell."


nucleus

A nucleus is a central part about which other parts are grouped together.  In an atom, it is the center.