2. John Dalton’s Atomic Theory 1.Matter is composed of atoms. Atoms are composed of protons, neutrons and electrons 2.All atoms of the same element are identical 3.Atoms of different elements are different 4.During a chemical reaction, atoms combine to form new products

3. John Dalton’s Atomic Theory Each element has a different size because: # of atoms # of electrons Therefore: the higher the atomic number, the bigger the atom of the element will be. H O H

4. Organization of Matter Elements – building blocks of the universe *made up of atoms Atoms – smallest unit of matter *made up of protons, neutrons and electrons Protons and Neutrons make up the NUCLEUS of the atom Electrons are located on SHELLS orbiting the nucleus * also called orbitals

5. Organization of Matter Molecules – combination of 2 or more atoms *made up of same OR different atoms (eg. CO2 or O2) Compound – molecule of different atoms *H2O, CO2… Chemical Formula – shows us how many of each atom in a molecule

6. Periodic Table A list of elements and their properties Arranged by Rows called PERIODS Columns called FAMILIES Reading horizontally, the elements atomic numbers increase by 1 Elements in the same family all have the same number of electrons in their outer shells* * later slides explain

7. Chemical Symbols All elements have a chemical symbol eg. C = Carbon Na = Sodium *1 st letter is CAPITALIZED, 2 nd is small – VERY IMPORTANT!!!

8. Atomic Number. Tells us the how many protons are in the nucleus AND How many electrons on the shells

9. Shells or Orbitals Like the moons of a planet, ELECTRONS orbit the atoms nucleus Each shell has a maximum capacity Shell #1 – 2 Electrons Shell #2 – 8 Electrons Shell #3 – 8 Electrons Shell #4– 8 Electrons

10. Insert copy of the periodic table.

11. Rows on the periodic table are called periods. All the elements listed in a row belong to the same period. There are 7 (seven) periods.

12. Columns in the periodic table are called groups or families. All elements in a group have similar properties.

13. Insert copy of the periodic table. The columns have been given an Arabic number. The columns are numbered 1 – 18 starting at the left and moving to the right. Please make sure that your periodic table has them numbered like this.

14. Group 1 and 2 the number of Valence electrons in the outer energy level will match the group number. Insert picture of periodic table.

15. Groups 3 through 12 do not follow any particular rule to determine the number of Valence electrons. Insert picture of periodic table.

16. Group 13 to 18 – The Valence electrons for each of these is the group number less 10. For example Group 14 – 10 = 4 Valence electrons. Insert picture of periodic table.

17. Elements whose atoms gain, lose or share electrons are reactive and they combine to form the many compounds we use in our daily lives.

18. Elements are categorized as metals, nonmetals or metalloids. Metals: An element that has luster, is malleable and ductile, and is said to be a good conductor of heat and electricity.

19. Luster describes the way a surface reflects light…therefore metallic luster would be shiny like a metal object. Malleable means to be able to press or pound the substance into sheets or different shapes. What is luster, malleable and ductile? Ductile means that the substance can be drawn out into thin wires.

20. Elements are categorized as metals, nonmetals or metalloids (cont’). Nonmetals: an element that is usually a gas or a brittle solid at room temperature. It is a poor conductor of heat and electricity.

21. Elements are categorized as metals, nonmetals or metalloids (cont’). Metalloid: an element that shares some characteristics or properties with both metals and nonmetals.

22. Group 1 and 2 Elements: These elements are so reactive that they are only found combined with other elements in nature.

23. 3 Li Lithium 6.941 11 Na Sodium 22.990 19 K Potassium 39.098 37 Rb Rubidium 85.468 55 Cs Cesium 132.905 87 Fr Francium 223.020 Group 1: Alkali Metals Soft – can be cut with a knife Shiny and silver colored Low Density (some will even float) Most reactive of the metals Valence electrons = 1 Reacts violently with water forming a hydrogen gas Compounds from these are very useful such as NaCl

24. 4 Be Beryllium 9.012 12 Mg Magnesium 24.305 20 Ca Calcium 40.078 38 Sr Strontium 87.62 56 Ba barium 137.327 88 Ra Radium 226 Group 2: Alkaline- Earth Metals Very reactive but not as reactive as Alkali Metals. Silver colored More dense than Group 1 metals Valence electrons = 2 Useful compounds include: Calcium compounds such as cement, plaster, chalk, and YOU.

25. 6 C Carbon 12.011 14 Si Silicon 28.086 32 Ge Germanium 72.64 50 Sn Tin 118.710 82 Pb Lead 207.2 Group 14: Carbon Group Reactivity varies in this group depending on the element Valence electrons = 4 This group contains 2 metals, 1 nonmetal and 2 metalloids. Many forms found uncombined in nature such as diamonds Compounds are very useful: proteins, fats, carbohydrates, computer chips.

26. 1 H Hydrogen 1.008 Hydrogen Stands Alone: Properties do not match the properties of any single group Valence Electrons = 1 Easily looses that one valence electron Physical properties are like the nonmetal group Most abundant element in the Universe Its reactive nature makes it useful as a fuel for rockets.

27. The outer most energy level is usually not full or complete. Valence electrons are important because they determine how an element will react with other substance. These electrons in the outer energy level are called Valence electrons. Valence Electrons

28. The outer most energy level is usually not full or complete. Valence electrons are important because they determine how an element will react with other substance. These electrons in the outer energy level are called Valence electrons. Valence Electrons