2009 compounds2
TRANSCRIPT
Compounds
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 in groups 3 through 12 are called
A. halogens
B. noble gases
C. transition metals
D. alkali metals
Atoms combine together to form most of the substances we observe in the world around us.
Compounds - two or more atoms 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. 9
D. 20
5. The ratio between the atoms that form a compound is indicated by the
A. coefficients
B. quotient
C. superscripts
D. subscripts