1. A column in the periodic table.
2. One type of atom.
3. These run from left to right.
4. Maximum number of electrons in the 2nd shell.
5. A non metallic element
6. The isotope of Hydrogen with two neutrons.
7. Fluorine, bromine, chlorine, iodine are described as this on the periodic table.
8. Energy level of an atom
9. The total number of this particle plus the number of neutrons is called the mass number.
10. Element which is electrically neutral and has 6 electrons
11. Negatively charged particle
12. Metals are found on this side of the periodic table.