1 4,18. 2  Shingles in caused by the same virus that causes chickenpox-varicella-zoster virus. 3  Shingles is a painful infection of the nerve supplying an area of skin and is accompanied by a localised skin rash.
The electrons on the outermost energy level of the atom are called valence electrons. The valence electrons are involved in bonding one atom to another. The attraction of each atomâs nucleus for the valence electrons of the other atom pulls the atoms together.
Boron has three valence electrons. It is in group 13. 1st energy level ------- 2 e-. 2nd energy level-------8 e-. 3rd energy level ------3 e-. Outermost energy level is the the 3rd energy level and it has three electrons. Valence electrons are the electrons in the last energy level of an atom.