The Modern Periodic Table

1. The Modern Periodic Table

2. Early Periodic Table – Atomic Number • In 1913 Henry Mosley discovered that each element contained a unique number of protons in the nuclei • Arranged elements in order of atomic number. • Resulted in a clear periodic pattern of properties.

3. Periodic Law • There is a periodic repetition of chemical and physical properties of elements when arranged in increasing atomic number (increasing number of protons) called the periodic law

4. Modern Periodic Table • Organized in columns called groups or families • Rows are called periods • Group A – representative elements (1A-8A) • Group B - transition elements (1B-8B) Representative Elements (Group A) Representative Elements (Group A) Transition Elements (Group B)

5. Classification of Elements • Three classifications for elements metals, nonmetals, and metalloids (semimetals).

6. Metals • Properties of Metals • shiny, smooth, solids (except mercury) • Good conductors of heat and electricity • High densities • High melting and boiling points • Malleable – bended or pounded into sheets • Ductile – drawn into wires

7. Groups of Metals • Alkali metals – group 1A except H • Alkaline earth metals – group 2A • Alkali metals and alkaline earth metals are chemically reactive • Transition metals – group B elements • Inner transition metals • Lanthanide • Actinide

8. Metals (blue) Alkali Metals Alkaline Earth Metals Transition Metals (B group elements) Inner Transition Metals

9. Organizing by Electron Configuration • Group number for group A elements represents the number of valence electrons • Atoms in the same group have similar chemical properties because they have the same number of valence electrons

10. Alkali Metals • Electron configurations for alkali metals • Lithium 1s22s1 [He]2s1 • Sodium 1s22s22p63s1 [Ne]3s1 • Potassium 1s22s22p63s23p64s1 [Ar]4s1 • Rubidium 1s22s22p63s23p64s23d104p65s1[Kr]5s1 • What do the four configurations have in common? • They have a single electron in their outermost energy level • They all have one valence electron, thus similar chemical properties

11. Alkaline Earth Metals • Electron configuration for alkaline earth metals • Beryllium [He]2s2 • Magnesium [Ne]3s2 • Calcium [Ar]4s2 • Strontium [Kr]5s2 • All alkaline earth metals have two valence electrons, thus similar chemical properties.

12. Nonmetals (yellow) Noble Gases Halogens

13. Nonmetals • Gases or brittle, dull looking solids • Poor conductors of heat and electricity • Usually have lower densities, melting point, and boiling point than metals. • Groups of nonmetals • Halogens 7A • Noble gases 8A sulfur

14. Noble Gases • Noble gases – Group 8A • Called inert gases because they rarely take part in a reaction He – 1s2 Ne – 1s22s22p6 Ar – 1s22s22p63s23p6 Kr - 1s22s22p63s23p63d104s24p6 • Because noble gases have completely filled s and p sublevels, they do not react with other elements

15. Metalloids (Semimetals) • Physical and chemical properties similar to both metals and nonmetals • They are metallic-looking brittle solids • Relatively good electrical conductivity. • Used in glasses, alloys, and semiconductors • The six elements commonly recognized as metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Polonium and astatine are sometimes classified as metalloids

16. Metalloids aka Semi-metals(pink)

18. Color in your work packet!!! • Choose 6 colors to color your key. • Use the CP books on page 162-163 to color your periodic tables