Notes: Compounds
CW: Counting Atoms
H: Chemical Compounds
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.
Compounds
January 25, 2010
Objectives1. Define compound, molecule,
chemical formula, diatomic molecule
2. Write and decipher a chemical formula
1. Elements with 7 valence electrons are
A. metalloids
B. noble gases
C. transition metals
D. halogens
2. The elements to the left of the zigzag line on the periodic table are
A. gases
B. metals
C. nonmetals
D. metalloids
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
4. Elements between groups 2 and 3 are called
A. halogens
B. noble gases
C. transition metals
D. alkali metals
Compounds - two or more elements chemically joined together to form a new substance with very different propertiesproperties than the elements of which it is formed.
Molecule
The smallest piece of a compound is that still has all of the properties of the compound.
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.
H2O
If there is a number in front of the formula, it tells you how many MOLECULES of that substance:
4H2O
This number is called the coefficient.
C6H12O6
3CO2
Ba(NO3)2
2Al2(SO4)3
diatomic moleculeWhen an element consists of two identical atoms it is called DIATOMIC molecule.
O2
7 elements are always found as diatomic molecules - Iodine, Hydrogen, Nitrogen, Bromine, Oxygen, Chlorine, Fluorine
I Have No Bright Or Clever Friends
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
2. The groups of symbols that represent a compound is called a chemical
A. recipe
B. formula
C. function
D. combination
3. How many calcium atoms are present in Ca(ClO3)2?
A. 1
B. 3
C. 9
D. 17
4. In the formula 5 CaSO4, the total number of sulfur atoms present is
A. 1
B. 5
C. 20
D. 30
5. The way a chemical formula tells how much of one element is present as compared to another element is indicated by the…
A. coefficientsB. quotientC. superscriptsD. subscripts