The document provides information about chemical compounds and formulas: 1. It defines a compound as two or more elements chemically joined together to form a new substance with different properties than the elements. 2. It explains that a molecule is the smallest piece of a compound that retains the compound's properties. 3. It describes how chemical formulas use subscripts to indicate the number of atoms of each element in a compound, and coefficients to indicate the number of molecules.

1. Notes: Compounds CW: Counting Atoms H: Chemical Compounds

2. Unit Project Wanted Poster Tomorrow will be a project work day You will receive the full rubric tomorrow I will give you a list of websites to use Parts will include what the element is, who found it, characteristics of the element, and a picture of the element in use.

3. Compounds January 25, 2010

4. Objectives Define compound, molecule, chemical formula, diatomic molecule Write and decipher a chemical formula

5. 1. Elements with 7 valence electrons are A. metalloids B. noble gases C. transition metals D. halogens

6. 2. The elements to the left of the zigzag line on the periodic table are A. gases B. metals C. nonmetals D. metalloids

7. 3. A very stable electron arrangement of valence electrons is a characteristic of what chemical family? A. alkali metal B. halogen C. noble gas D. alkaline earth

8. 4. Elements between groups 2 and 3 are called A. halogens B. noble gases C. transition metals D. alkali metals

9. Compounds - two or more elements chemically joined together to form a new substance with very different properties than the elements of which it is formed.

10. + Sodium + Chlorine = Salt =

11. Molecule The smallest piece of a compound is that still has all of the properties of the compound.

12. Chemical Formulas: The subscripts to the right of the letters tell you HOW MANY ATOMS of each element. If there isn’t one, it means that there is one atom of that element. H 2 O

13. If there is a number in front of the formula, it tells you how many MOLECULES of that substance: 4H 2 O This number is called the coefficient.

14. C 6 H 12 O 6 3CO 2 Ba(NO 3 ) 2 2Al 2 (SO 4 ) 3

15. diatomic molecule When an element consists of two identical atoms it is called DIATOMIC molecule. O 2 7 elements are always found as diatomic molecules - I odine, H ydrogen, N itrogen, B romine, O xygen, C hlorine, F luorine I H ave N o Br ight O r Cl ever F riends

17. 1. Electrons in the outermost energy level are involved in the chemical combining of elements to form A. acids B. compounds C. gases D. metalloids

18. 2. The groups of symbols that represent a compound is called a chemical A. recipe B. formula C. function D. combination

19. 3. How many calcium atoms are present in Ca(ClO 3 ) 2 ? A. 1 B. 3 C. 9 D. 17

20. 4. In the formula 5 CaSO 4 , the total number of sulfur atoms present is A. 1 B. 5 C. 20 D. 30

21. 5. The way a chemical formula tells how much of one element is present as compared to another element is indicated by the… A. coefficients B. quotient C. superscripts D. subscripts