2009 compounds2

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.

+

Sodium + Chlorine = Salt

=

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