The “lead” of a pencil is actually made of a substance called graphite which is made of carbon atoms. The picture shows a close-up of one carbon atom. A hydrogen atom has one proton as the nucleus and ...

The protons and neutrons are contained in the nucleus ... This shows that lithium atoms have three electrons, two in the first shell and one in the second shell. Sodium has 11 electrons.

This energy level model shows two electrons on the first energy level and six electrons on the second energy level. Since this atom has a total of eight electrons, it also has eight protons ... 2nd ...