ELEMENTS AND ATOMS NOTES

1. ELEMENTS AND ATOMS NOTES

2. Matter and Atoms • Matter is anything that takes up space and has mass • There are 4 phases of matter solid, liquid, gas, and plasma. • All matter is made of atoms. • Atoms are the building blocks of matter, sort of how bricks are the building blocks of houses.

3. The Atomic Model • An atom has three parts. • Protons are positive and in the nucleus of the atom. • Neutrons have a neutral charge and are also found in the nucleus. • Electrons have a negative charge and they orbit the atom in what is known as an electron cloud. • Brain Pop Atoms Movie

4. John Dalton-The Atomic Man • John Dalton was an English chemist. • He came up with the many of the ideas that we still utilize today about atoms and the way they are represented. • Through his research Dalton developed 5 postulates or things he believed about atoms.

5. Dalton’s Postulates • Every element is composed of tiny particles. • These particles are called atoms. • All atoms of a given element are identical, atoms of different elements have different properties. • Atoms of an element are NOT changed into atoms of another element through chemical processes. Matter can not be created nor destroyed. • Compounds are formed when atoms of more than one element combine.

6. Dalton’s Laws • Law of Constant Composition is that “any given compound always consists of the same atoms and the same ratio of atoms. • For example, water always consists of oxygen and hydrogen atoms, and it is always 89% oxygen by mass and 11% hydrogen by mass.

7. Dalton’s Laws • Law of Conservation of Mass is that the total mass of materials before and after a chemical reaction must be the same. • Matter can not be created or destroyed during a chemical reaction. • The mass of the reactants should be equal to the mass of the products.

8. Elements • Elements are the alphabet to the language of molecules. • To make molecules, you must have elements. • Elements are made of atoms. While the atoms may have different weights and organization they are all built the same way. • Elements can not be broken down into smaller substances by chemical or physical means. • Elements contain one type of atom(s). • Element Song

9. Naming the Elements • The first 103 elements have internationally accepted names, which are derived from: • The compound or substance in which the element was discovered. • An unusual or identifying property of the element. • Places, cities, and countries. • Famous scientists. • Greek Mythology • Astronomical objects.

10. Different types and versions of atoms

11. More Information about Elements • Elements are the building blocks of all matter. • The periodic table is a list of all of the elements that can build matter. It’s a little like the alphabet of chemistry. • The periodic table tells us several things…

12. Periodic Table Basics Atomic Number: Number of protons and it is also the number of electrons in an atom of an element. 8 O Element’s Symbol:An abbreviation for the element. Oxygen Elements Name 16 Atomic Mass/Weight: Number of protons + neutrons.

13. Atomic Mass= (#P) + (#N) Atomic Number tells how many protons For every proton (+) there is an electron (-) Atomic mass number tells haw many P and N number tells haw many P and N

14. Practice Open your books to page L*169 and use the periodic table for the practice elements. Fluorine Symbol= Atomic #= Atomic Mass= # P= #E= #N=

15. Practice Boron • Symbol= • Atomic #= • Atomic Mass= • # P= • #E= • #N= Zinc • Symbol= • Atomic #= • Atomic Mass= • # P= • #E= • #N=

16. Structure of an Atom Nucleus (protons and neutrons) 1stshell =2 electrons 2ndshell =8 electrons 3rdshell =8 electrons 4thshell =18 electrons

17. Electron Rules • You can’t just shove all of the electrons into the first orbit of an electron. • Electrons live in something called shells. • Only so many can be in any certain shell. • The electrons in the outer most shell of any element are called valence electrons

18. Different Atomic Models • There are two models of the atoms we will be using in class. • Bohr Model and the Lewis Dot Structure

19. The Bohr Model • The Bohr Model shows all of the particles in the atom. • In the center is circles. Each circle represents a single neutron or proton. Protons should have a plus or P written on them. Neutrons should be blank or have an N. • In a circle around the nucleus are the electrons. Electrons should have a minus sign or an e.

20. Let’s Draw LITHIUM!!!!!!! • How to draw a Lithium atom • First, look at the Periodic Table • Second, determine the number of protons (Look @ the atomic number) • Then determine the number of neutrons (Atomic mass – atomic number) • Then determine the number of electrons (Look @ the atomic number) 3 Li Lithium 7

21. - - - - - - - - + + + + + + + + The Lewis Dot Structure for Oxygen • The Lewis Dot Structure is a bit different from the Bohr model. • It only shows the element symbol and it’s outer most electron shell. • • O • • • •

22. Lewis Dot Structure for Lithium • Write the symbol. • Start on the right hand side, working your way clockwise around the symbol. • Try Lithium

23. Practice Magnesium • Symbol= • Atomic #= • Atomic Mass= • # P= • #E= • #N= Now Draw the Atom in both Bohr and Lewis Dot Structure: