1. Chapter14: Periodic Trends Modern Chemistry; Holt, Rinehart, & Winston

2. Russian chemist Arranged his periodic table according to atomic mass so that elements with similar properties were in the same group Predicted the properties of elements that had not yet been discovered using his periodic table Russian chemist Arranged his periodic table according to atomic mass so that elements with similar properties were in the same group Predicted the properties of elements that had not yet been discovered using his periodic table Dmitri Mendeleev (1834-1907)

3. English chemist Proved Mendeleev’s arrangement of the periodic table to be correct – only, the periodic table was arranged according to atomic number, not atomic mass English chemist Proved Mendeleev’s arrangement of the periodic table to be correct – only, the periodic table was arranged according to atomic number, not atomic mass Henry Moseley (1887-1915)

4. The Periodic Law States that when elements are arranged in order of increasing atomic number, their physical and chemical properties show a periodic pattern

5. Atomic Radii Atomic radius – the distance between the center of the nucleus and the outer most energy level Distance between nuclei Atomic Radius

6. Decreases across a row

7. Group Trends Increase down a group

8. Which element has a larger atomic radius? Na or K? Al or Cl? F or Sn? Fr or O? Na or K? Al or Cl? F or Sn? Fr or O? K Al Sn Fr

9. Ionization Energy The energy required to remove one electron from a neutral atom of an element creating an ion

10. Ionization Energy Increase across a period

11. Group Trends Decrease down the group

12. Which element has a greater ionization energy? Ca or Br? C or Ge? Ba or Cl? Br or Pb? Ca or Br? C or Ge? Ba or Cl? Br or Pb? Br C Cl Br

13. Electronegativity A measure of the ability of an atom in a chemical compound to attract a bonding pair of electrons A MEASURE OF GREEDINESS! A measure of the ability of an atom in a chemical compound to attract a bonding pair of electrons A MEASURE OF GREEDINESS!

14. Electronegativity Increase across a period Decrease down a group EXCEPTIONS: NOBLE GAS (GROUP 18). They do not have an electronegativity value because they do not form chemical compounds. Increase across a period Decrease down a group EXCEPTIONS: NOBLE GAS (GROUP 18). They do not have an electronegativity value because they do not form chemical compounds.

15. Which element has a greater electronegativity? Mg and Ba? Zn or Br? Xe or I? Ge or Ne? Mg and Ba? Zn or Br? Xe or I? Ge or Ne? Mg Br I Ge