Elements and Compounds

1. Elements and Compounds

2. What is matter? • Matter is always in the form of a liquid, solid, or gas. What makes up liquids, solids, and gases? ELEMENTS! • Elements are the building blocks of matter. That means elements are the purest substance possible. They CANNOT be broken down into simpler substances.

3. Elements • Examples of Elements include: Helium (He), Hydrogen (H), and Oxygen (O). • There are a total of 118 elements that have been discovered.

4. Periodic Table of Elements

5. What are elements made of? • Atoms: the smallest unit of an element that has the properties of that element • Atoms were first discovered by John Dalton in 1803. • Atoms are so tiny they can only be seen with a scanning tunneling microscope.

6. What is inside an ATOM? • Protons: carry a positive charge and are located in the nucleus of the atom • Neutrons: carry a neutral (or no) charge and are located in the nucleus of the atom • Electrons: carry a negativecharge and are located in a “cloud” (a space surrounding the nucleus called an electron cloud) and are arranged in “shells”

7. What are compounds? • A compound is formed when two or more elements are combined in a chemical reaction and act like a single substance. • An example of a compound is water (H2O) orcarbon dioxide(CO2). Plants take in carbon dioxide.

8. What are molecules? • A molecule is a particle that contains more than one atom chemically bonded together. • An example of a molecule is that oxygen can appear as O2 (what you breathe)or O3 (the ozone).

9. Can be Broken down By a chemical reaction Made up of two or more elements Made up of one or more atoms Purest form of matter Water H2O COMPOUNDS ELEMENTS Made of elements Make up matter Building Blocks of Matter Their symbols are called chemical formulas. Cannot be broken down

10. Mixtures • A mixture is a combination of different things. • A homogeneous mixture is a mixture that is the same everywhere. Another name for it is a solution. An example would be salt water. When you mix salt and water, the water is the same on the top as it is on the bottom. • A heterogeneous mixture is not the same everywhere. Examples would be sand or ice water.

11. Parts of a Mixture • The substance that makes up the smaller part of the mixture is called the solute. • The larger part of the mixture is called the solvent. • If you were making iced tea, the water would be the solvent. The tea mix would be the solute.

12. Chemical Reactions • A chemical reaction occurs whenever bonds between atoms and molecules are created or destroyed. • When a bond is created, the molecules form a new product. • Example: Sodium (Na) and Chlorine (Cl) react together by combining to form Sodium Chloride (NaCl). Salt

13. Chemical Reactions 4. Example: When iron is left outside, it reacts with oxygen, and rust forms. • Example: Stomach acid digests food.

14. Is it a chemical reaction? • Are there bubbles being released when you add something to something else? (The matter may change phase and have new behavior.) • When mixing two solutions, does one solution change color? • Does the temperature change when you add one solution to another? • Does a precipitate form? A precipitate looks like colored sand, mud, dust, or snow forming in the solution. It lets us know new molecules were made.

15. Gold (Au) Silver (Ag) Tin (Sn) Lead (Pb) Neon (Ne) Mercury (Hg) Sulfur (S) Chlorine (Cl) Fluorine (F) Carbon Dioxide Carbon Monoxide Sodium Chloride Hydrogen Peroxide Water Baking Soda Ammonia Rust Sulfuric Acid Elements and Compounds

16. Element Research (choose an element to study)