Electric current is a flow of electrons- minute particles far too small to see through any microscope- that are
dislodged from atoms. the greater and faster the flow of electrons, the bigger the current. But it takes a flow of billions of electrons to make even a small current.
Atoms are the tiny particles that make up all matter. The much tinier electrons orbit around the atom's nucleus in a probability function orbit path called as shells or Orbitals. Each shell may consist of a different numbers of electrons.
An atom is usually electrically neutral because the two charges between positively-charges nucleus and negatively-charged electrons are cancelled out. An atom that loses or gains electrons becomes electrically charged and is called an ion.
An electric current will not flow through a circuit unless there is an excess of electrons at one end and a deficiency at the other. This is known as Potential Difference.