The Modern Periodic Table

1. The Modern Periodic Table Chapter 5.2

2. Element Information in the Periodic Table • Most often there are 4 pieces of information for each element listed on the periodic table.

3. Element Information in the Periodic Table • Most often there are 4 pieces of information for each element listed on the periodic table. Atomic number (# of protons)

4. Element Information in the Periodic Table • Most often there are 4 pieces of information for each element listed on the periodic table. Atomic number Element symbol (1st capital, 2nd small)

5. Element Information in the Periodic Table • Most often there are 4 pieces of information for each element listed on the periodic table. Atomic number Element symbol Element name

6. Element Information in the Periodic Table • Most often there are 4 pieces of information for each element listed on the periodic table. Atomic number Element symbol Element name Atomic mass

7. Atomic Mass • Atomic mass depends on: • Distribution of an element’s isotopes • Masses of those isotopes. • Isotopes = same element, different masses • Masses different because: • Same # protons • Different # neutrons

8. Atomic Mass • Atomic Mass Units • Scientists chose one isotope to serve as a standard. • This isotope is the most abundant one found in nature • Carbon-12 atom: 6 protons and 6 neutrons. • 1 Atomic Mass Unit (amu) = one twelfth the mass of a carbon-12 atom.

9. Most elements are mixtures of 2 or more isotopes. • Atomic mass is weighted average. • Example: Chlorine atomic mass = 35.453 amu. • Two natural isotopes of chlorine: chlorine-35; chlorine-37 • Chlorine-35: 17 protons and 18 neutrons. • Chlorine-37: 17 protons and 20 neutrons.

10. The Periodic Law • Elements in modern periodic table arranged by increasing atomic number (not mass) • (Atomic number = # of protons). • Periodic Law - Pattern of Repeating Properties • Periods - Each row is a period. • Each period is for a different electron shell or energy level

11. All of the Electron Shells

13. The Periodic Law • Modern periodic table – stretched out (7 rows) • Shows periods with Lanthanide & Actinide series where they really belong

14. The Periodic Law • Elements are also arranged into vertical columns called Groups (or Families). • Sounds of musical notes separated by an octave are related, but they are not identical. • Properties of elements in a Group (column) are related, but not identical. • Groups- Each column is a Group (or Family). • Similar electron configurations • Similar chemical properties

16. Example: Group 8A (or 18)- Noble Gasses with Full Shells Helium - Atomic #2 Neon - Atomic #10 Argon - Atomic #18

17. The Periodic Law Periodic Table of the Elements

18. Metals • Largest class of elements on the Periodic Table - Metals. • 80% of the elements.

19. Physical Properties of Metals • Malleable and ductile (can change shape) • Malleable = compress without breaking • Ductile = stretch without breaking • Good Conductors (thermal & electrical) • Luster (means they are shiny!)

20. Transition Metals • Groups 3 – 12: Form a bridge between elements on the left and right side of the table • Tough, hard, and strong • Less reactive than standard metals • Have more properties in common than elements in other groups.

21. Metalloids • Share characteristics of both metals & non – metals. • Semi – conductors

22. Non-Metals • Insulators (poor conductivity) • Living organisms are mostly non-metals. (especially C, N, O, H) • Most of the compounds in your body contain carbon

23. Variations Across a Period • Across a period from left to right, the elements become less metallic and more nonmetallic in their properties. • From left to right across Period 3, there are three metals (Na, Mg, and Al), one metalloid (Si), and four nonmetals (P, S, Cl, and Ar).

24. Variations Across a Period • Sodium reacts violently with water. • Magnesium will not react with water unless the water is hot. • Aluminum does not react with water, but it does react with oxygen. • Silicon is generally unreactive. • Phosphorus and sulfur do not react with water, but they do react with oxygen. • Chlorine is highly reactive. • Argon hardly reacts at all.