2. When you hear/see the word “ATOM” you can always assume that it is referring to the element in it’s NEUTRAL state A NEUTRAL ATOM means that there are the SAME number of positively charged PROTONS as there are negatively charged ELECTRONS (the two charges balance out to zero) Example: Nitrogen has +7 charge (protons) and -7 charge (electrons) = 0 charge REMINDER

3. Atoms can gain or lose electrons This causes them to become electrically charged IONS = electrically charged atoms that have gained or lost electrons IONS

4. Atoms will either lose some electrons or gain some electrons to become more stable The most stable state for an atom is with a full octet (8 electrons in its valence shell) The Noble Gases are all stable octets. Other atoms will gain or lose electrons to be stable like their nearest noble gas is WHY DO IONS OCCUR?

5. Metal atoms lose e- to form positively charged cations Example: Na loses 1 electron to become the ion Na + CATIONS

6. Metal ions (cations) tend to lose electrons to become more stable Example: Na atom has + 11 protons And - 11 electrons = 0 electric charge But that one electron in it’s outer shell makes it unstable, so it will get rid of it and have the inner full shell its new valence shell Example: Na ion has + 11 protons And - 10 electrons = +1 electric charge METAL IONS

7. SODIUM ATOM VS. ION Sodium ATOM (above) vs Sodium ION (above) Notice that the ATOM has the SAME number p+ and e- Notice that the ION has 1 LESS electron than protons

8. Non-metal atoms gain e- to form negatively charged anions Example: Cl picks up 1 electron to become the ion Cl - ANIONS

9. Non-metal ions (anions) tend to gain electrons to become more stable Example: Cl atom has + 17 protons And -17 electrons = 0 electric charge But that one electron missing in it’s outer shell makes it unstable, so it will pick up one to make its valence shell full Example: Cl ion has + 17 protons And -18 electrons = -1 electric charge NON-METAL IONS

10. CHLORINE ATOM VS. ION Chorine ATOM (above) vs Chlorine ION (above) Notice that the ATOM has the SAME number p+ and e- Notice that the ION has 1 MORE electron than protons

11. HOW TO WRITE/SHOW AN ION To write/show an ion, surround the element symbol with brackets, and write the new charge just outside the brackets in the top right

12. Metals lose electrons. Electrons are negatively charged. Each negative electron a metal atom loses makes it that much more positively charged (it gets less negative). Non-metals gain electrons. Electrons are negatively charged. Each negative electron a non-metal gains makes it that much more negatively charged (it gets more negative). CHARGES

13. Don’t worry, we will go over some together… right now! QUESTIONS?