Basics concepts of electronics

• atom-smallest particle of an element
• nucleus- consist protons & neutrons 
• proton- positively charge particles
• neutrons- uncharged particles
• electrons - negatively charged particles
• simplest atom hydrogen - one proton & one electron
• atomic number- number of protons in the nucleus
• shells- orbits are grouped into energy levels 
• The Maximum Number of Electrons in Each Shell -Ne= 2n٨2
• valence shell- outermost shell
• valence electrons- electrons in the outermost shell
• mass-Protons and neutrons are approximately the same mass.
• mass of electron-1/1836 of a proton
• quarks - smaller particle within the protons and neutrons