1. PERIODIC TRENDS: 1. ATOMIC RADIUS 2. IONIC RADIUS What is the atomic radius? What is an ion? What is the ionic radius? How does it change going across and down?

2. What is a radius? Half of diameter as measured from center of circle

3. What is an Atomic Radius? half of the distance between the two adjoining nuclei of atoms

4. Some elements occur stuck together naturally!

5. What are the seven diatomic elements? Diatomic Elements: two elements joined together Bromine (Br 2 ) Iodine (I 2 ) Nitrogen (N 2 ) Chlorine (Cl 2 ) Hydrogen (H 2 ) Oxygen (O 2 ) Fluorine (F 2 ) Made easy to remember…. Br I N Cl H O F (like a last name Brinclhof)

6. Br I N Cl H O F Where are they on the periodic table?

7. Atomic Radius Trend In groups = as atomic number increases In periods = as atomic number increases Is there a part missing?

8. Trends show general rules

9. WHY? In groups: adding more energy levels In periods: size of nuclear charge

10. What is an ion? A ✚ or − charged atom Occurs when atom loses or gains electrons

11. CATION see a + ion metals lose e- and become more + become smaller Atom: 11 p+ 12 n 11 e- n=3 Overall charge = 0 Ion: 11p+ 12 n 10 e- n=2 Overall charge = +1

12. ANION A negative ion, a – ion NONmetals gain e- and become more – become larger Atom 9 p+ 9 e- Overall Charge = 0 Ion 9 p+ 10 e- Overall Charge = -1

13. IONIC RADIUS TREND Ionic size changes b/c: CATIONS get smaller as e- are drawn in closer by + nuclear charge ANIONS get bigger as e- cloud spreads out

14. IONIC RADIUS TREND In groups = increase as you go b/c more energy levels In periods = as you go across b/c e- cloud shrinks as e- are lost