electron configuration

• each energy level or shell has a "principle quantum number"
• orbital is a region of space that holds up to 2 electrons
• electrons always try and spin in opposite directions since they refract each other
• ions also have an electronic configuration
• cations are positive ions that have lost electrons
• anions are negative ions that have gained electrons
• the 4s orbital gets filled before the orbital 3d
• Cu and Cr put an extra electron in the 3d orbital but put 1 less in the 4s orbital
• to write a short structure you can use the last noble gas and then the rest of it