Whats a electron?
An electron is a negatively charged particle located in the electron cloud surrounding the nucleus of an atom. It is about 1/2000 the mass of a proton or neutron.
Whats the similarity of a compound light microscope Transmission Electron Microscope and Scanning Electron Microscope?
almost everything on this earth wants stability which is achieved by bonding bond means to join. atoms achiev stability by somehow making the number of electron in the valence shell 8 (2 in case of helium) So when two non metallic atoms join together by sharing their valence electron so both of them atom can have 8 valence electron for themselves.This type of bonding is called covalent bond.