SNC1D1 Grade 9 Science
Name: ________________________
Date: _________________________
Making Compounds
Ionic Compounds
Ionic compounds are made up of oppositely charged ions (METAL + NONMETAL)
How can a sodium atom get rid of its extra electron to
become chemically stable?
The positive ion that is formed is:
How can a fluorine atom get the extra electron it needs
to make it table?
The negative ion that is formed is:
The elements have now formed an ionic compound called “sodium fluoride” and has the chemical formula, NaF.
(This is a key ingredient in toothpaste!)
The atoms are held together by an ionic bond which is a strong attraction between positive and negative ions
(recall: opposite charges attract, similar charges repel).
Note: all ionic compounds formed are “neutral”; meaning the number of positive charges equals the number of
negative charges.
The example above shows bonding between all alkali metals and halogens!
Let’s Practice! In your notebook, show by drawing Bohr-Rutherford diagrams how the following ionic compounds
are made: LiF, NaCl, and KBr.
Example #2: Magnesium and Oxygen
How can a magnesium atom get rid of its extra electrons
to become chemically stable?
The positive ion that is formed is:
How can an oxygen atom get the two electrons it needs
to make it table?
The negative ion that is formed is:
The elements have now formed an ionic compound is called _________________________ and has the chemical
formula __________
Example #3: Magnesium and Fluorine
The alkaline earth metals have a slightly different bonding pattern with the halogens (two halogens are required to
permit the electron rearrangement so that the alkaline earth metals can achieve a stable outer shell)
How can a magnesium atom get rid of its extra electron
How can a fluorine atom get the extra electron it needs
to become chemically stable?
to make it table?
The positive ion that is formed is:
The negative ion that is formed is:
The elements have now formed an ionic compound is called __________________________ and has the
chemical formula __________
Let’s Practice! Use Bohr-Rutherford diagrams to determine the chemical formula for the following pairs of
elements:
a) Beryllium and Oxygen
c) Lithium and Nitrogen
b) Sodium and Phosphorus
d) Calcium and Chlorine
Molecular Compounds
Molecular compounds are made up of uncharged atoms (NONMETAL + NONMETAL). They combine by SHARING
electrons in the valence shell. This type of bond is called a covalent bond.
Example #1: Hydrogen and Hydrogen
Example #2: Chlorine and Chlorine
Chemical formula:
Chemical formula:
Some elements are found as a pair in nature, like H2 and Cl2. These are called DIATOMIC MOLECULES.
 Remember the acronym BrINClHOF!
 Br2, I2, N2, Cl2, H2, O2, F2.
 These elements are always paired!!
Let’s Practice! Using Bohr-Rutherford diagrams show how atoms share electrons in the following compounds:
a) 2 Hydrogen and 1 oxygen (water)
c) O2
e) N2
b) 1 carbon and 2 oxygen (carbon dioxide)
d) F2
f) Br2