History and Properties of the Periodic Table

1. Chapter 5

2. Section1 History of the Periodic Table Chapter 5 Mendeleev and Chemical Periodicity • Mendeleev noticed that when the elements were arranged in order of increasing atomic mass, certain similarities in their chemical properties appeared at regular intervals. • Repeating patterns are referred to asperiodic. • Mendeleev created a table in which elements with similar properties were grouped together—a periodic table of the elements.

3. Section1 History of the Periodic Table Chapter 5 Mendeleev and Chemical Periodicity, continued • After Mendeleev placed all the known elements in his periodic table, several empty spaces were left. • In 1871 Mendeleev predicted the existence and properties of elements that would fill three of the spaces. • By 1886, all three of these elements had been discovered.

4. Properties of Some Elements Predicted By Mendeleev Section1 History of the Periodic Table Chapter 5

5. Section1 History of the Periodic Table Chapter 5 Moseley and the Periodic Law • In 1911, the English scientist Henry Moseley discovered that the elements fit into patterns better when they were arranged according to atomic number, rather than atomic weight. • The Periodic Lawstates that the physical and chemical properties of the elements are periodic functions of their atomic numbers.

6. Section1 History of the Periodic Table Chapter 5 The Modern Periodic Table • The Periodic Table is an arrangement of the elements in order of their atomic numbers so that elements with similar properties fall in the same column, or group.

7. Visual Concepts Chapter 5 Periodic Table Overview

8. Section 2 Electron Configurations and the Periodic Table

9. Section2 Electron Configuration and the Periodic Table Chapter 5 Periods and Blocks of the Periodic Table • Elements are arranged vertically in the periodic table in groups that share similar chemical properties. • Elementsare also organized horizontally in rows, orperiods. • The length of each period is determined by the number of electrons that can occupy the sublevels being filled in that period. • The periodic table is divided into four blocks, the s, p, d, and f blocks. The name of each block is determined by the electron sublevel being filled in that block.

10. Section2 Electron Configuration and the Periodic Table Chapter 5 Relationship Between Periodicity and Electron Configurations

11. Section 3 Periodic Trends

12. What are the trends?

13. Atomic Radius Down a group • Increases • Adding on extra electron orbitals • Stacking orbitals keep getting bigger Across a period • Decreases • More protons become ATTRACTED to more electrons

14. Section3 Electron Configuration and Periodic Properties Chapter 5 Atomic Radii, continued • Sample Problem E • Of the elements magnesium, Mg, chlorine, Cl, sodium, Na, and phosphorus, P, which has the largest atomic radius? Explain your answer in terms of trends of the periodic table.

15. Ionization Energy • Atom’s ability to steal an e- • Decreases down a group • Increases across a period Decreases Increases

16. Section3 Electron Configuration and Periodic Properties Chapter 5 Ionization Energy, continued Periodic trends in ionization energy are shown in the graph below.

17. Electronegativity • Atom’s ability to attract an e- • Decreases down a group • Increases across a period

18. Electron Affinity • Atom’s ability to accept an e- • Decreases down a group • Increases across a period Decreases Increases

19. Ionic Radii • Increases down a group • Cations decrease across a period • Anions decrease across a period