1. Atoms Molecules Elements

2. All matter is made up of particles (atoms and molecules)

3. Atoms No, not The Atoms Family!

4. These Atoms Atoms: The smallest particles of matter that can not be divided into smaller parts without changing their properties

5. Parts of an Atom

6. Parts of an Atom • Nucleus – Center of an atom • made up of protons and neutrons • Proton – Subatomic particle with a positive charge • Neutron – Subatomic particle with no charge • Electron – Subatomic particle with a negative charge

7. Protons and neutrons have a much larger mass than an electron. Protons and neutrons are about 2000 times the mass of an electron But… They both have equally strong charges! Proton/Neutron Hi there little guy! Who are you calling little? I’m just as strong as you! Electron

8. Electrons circle the nucleus in a fixed distance Orbits - The path in which electrons move

9. Part of what holds an atom together is the attraction between the positive protons and the negative electrons Proton Electron + or…. -

10. Hi there little guy! Who are you calling little? I’m just as strong as you! Man, those electrons sure are negative!

11. Elements Elements Substances made up of only one kind of atom. Cats are not elements!

12. Elements Substance made up on only one kind of atom Gold is an example There are more than 100 elements Most elements are solid at room temperature Only a few are gas or liquid at room temperature

13. Molecule Molecules are made up of 2 or more atoms joined together. A molecule is the smallest bit of a substance. Many elements occur as molecules, not just 1 atom.

14. Most elements are metals and are solid at room temperature Mercury and bromine are the only metals that are liquid at room temperature A thermometer Is an example of liquid mercury

15. Metals have familiar properties: Malleable– can be hammered into thin sheets Ductile – can be formed into wires Conduct - can transfer electricity Alloys are mixtures of metal such as bronze or steel

16. Insulators – conduct little or no electricity

17. Each element has an atomic number

18. For example: Hydrogen has only 1 proton in its nucleus So it has an atomic number of 1 Oxygen has 8 protons in its nucleus So it has an atomic number of 8 Let’s look at the Periodic Table to check out atomic numbers No, not that table!

19. Periodic Table Grouping of elements by similar properties Arranged by atomic number

20. Invented in 1869 by Dmitri Mendeleev, a Russian chemist • Each column of elements are a part of a group • (they often have same number of electrons in the outer energy levels of their atoms) • Elements on the left side are metals (except for hydrogen) • Elements on the far right are non-metals • Elements with properties of both metals & nonmetals are metalloids • Every element in the table is shown as an abbreviation known as the chemical symbol

21. Compounds – substance formed when the atoms of 2 or more elements combine.

22. When atoms join to form a compound, they go through a chemical change (the properties of the compound are different from the properties of the elements in it). Water is an example of a Compound H20

23. Chemical Formula Shows which elements and how many atoms of each are in a compound. Water H2O 2 hydrogen atoms join 1 oxygen atom Salt NaCl 1 sodium atom joins 1 chlorine atom Sugar (glucose) C6H12O6 6 carbon atoms 12 hydrogen atoms 6 oxygen atoms

24. And, now for fun….a bit of trivia Guess how many molecules you weigh! Amazingly, someone weighing 100 pounds, has about 916,778,800,000,000,000,000,000,000 molecules making up their body!  I had to look it up how to say that huge number here.  That's 916 septillion, 778 sextillion, 800 quintillion molecules in a 100 pound body!!

25. And Remember Never Trust an Atom They make up everything!