- Atom A (12P, 12N) is Magnesium (Mg), with electron configuration 2,8,2. It has 2 valence electrons and tends to lose them to achieve a stable octet.
- Atom B (8P, 8N) is Oxygen (O), with electron configuration 2,6. It has 6 valence electrons and tends to gain 2 electrons to achieve a stable octet.
When they form a bond:
- Mg loses 2 electrons to become Mg²⁺.
- O gains 2 electrons to become O²⁻.
After moving the electrons:
-
Atom A: Protons = 12+, Electrons = 10-, Difference = +2
-
Atom B: Protons = 8+, Electrons = 10-, Difference = -2
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1. If atom A loses electrons to atom B,
a. how many electrons will atom A lose?
2
b. how many electrons will atom B gain?
2
c. what will be the oxidation number of atom A?
+2
d. what will be the oxidation number of atom B?
-2
e. what will be the total charge of the compound formed?
0
f. what type of bond will form?
Ionic
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2. Explain why an element’s oxidation number is related to the group on the periodic table to which it belongs.
For Families 1, 2, 3, and 4 the oxidation number is
positive and equal to the group number (for main group elements).
For Families 5, 6, 7, and 8 the oxidation number is
negative and equal to (group number - 8), or sometimes positive for higher oxidation states in later groups.
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Directions: Complete the table comparing ionic compounds and covalent compounds.
| Characteristic | Ionic compounds | Covalent compounds |
|----------------------------|-------------------------|--------------------------|
| 3. How the compound is formed | electrons are transferred | electrons are shared |
| 4. Smallest particle | ion | molecule |
| 5. Usual state at room temperature | Solid | Solid, Liquid, Gas |
Parent Tip: Review the logic above to help your child master the concept of worksheet on chemical bonding.
