1. Lessons 3.1, 3.2A, 3.3 Period 1 Group 7

2. Lesson 3.1: The Elements A. Abundance of Elements  9 elements account for about 98% of the Earth’s crust, ocean and atmosphere  All materials in the universe can be broken down to 100 different elements  All elements have symbols

3. Lesson 3.1: The Elements What is the symbol for the element lead? Answer: Pb

4. Lesson 3.1: The Elements These are the some of the abundant elements that are found in Earth. N He C Fe

5. Lesson 3.1: The Elements B. Names and Symbols for the Elements -each element has a name and a symbol - usually consist of the first two letters of the element name. - the elements are named in different ways - some elements are named after scientists, or where the element was found. - some elements are named by their word origin.

6. Lesson 3.1: The Elements Example: How are most elements named? Answer: Elements are usually named by their word origin, founder, or places they were found.

8. Lesson 3.2: Atoms and Compounds Dalton’s atomic theory: -Elements are made up of atoms -all atoms of a element are identical -atoms of one element can combine with atoms of other elements to form compounds -atoms are indivisible in chemical processes

9. Lesson 3.2: Atoms and Compounds Example: What does a given compound always contain? Answer: It contains the same proportions of elements

10. Lesson 3.2: Atoms and Compounds This is the evolution of atomic theory

11. 3.3 Atomic Structure To learn about the terms: isotope, atomic number and mass number To understand Rutherford’s experiment

12. 3.3 Isotopes Isotopes are atoms with the same number of protons but different number of neutron. A particular isotope is represent by the symbol

13. 3.3 Isotopes Ex: what do Z, A and X stand for? -> A stands for the mass number Z stands for the atomic number X stands for the element’s symbol

15. 3.3 Atomic structure Experiments by JJ. Thomson showed that atoms contain electrons Ernest Rutherford showed that atoms have internal structure The nucleus is at the center of the atom Electrons move around the nucleus

16. What does nucleus contain? -> Nucleus contain proton ( positive charged ) and neutrons ( uncharged)

17. Ex : Atomic structure of Uranium (U)

18. References http://www.triumf.info/common/images/mids/vt4_hatom _450.jpg http://www.triumf.info/common/images/mids/vt4_hatom _450.jpg http://www.corrosionsource.com/handbook/periodic/pe riodic_table.gif http://www.corrosionsource.com/handbook/periodic/pe riodic_table.gif http://web1.caryacademy.org/chemistry/rushin/StudentP rojects/ElementWebSites/uranium/properties.htm

19. Quiz 1. What did the experiments of J.J Thomson show? 2. How many atoms does a microscopic have? 3. What is the law of constant composition? 4. What is Dalton’s atomic theory? 5. What are the charges of neutrons and protons?