Unit Four Review-Chemistry 2025

​Unit Four Review

By Rebecca May

Why do elements form bonds?

Why do elements form bonds?

To gain stability, reduce potential energy, and complete the octet rule.

What type of bond does Se and S form? (Ionic, polar covalent, nonpolar covalent)

What type of bond does Se and S form? (Ionic, polar covalent, nonpolar covalent)

2.6-2.5= 0.1 Nonpolar Covalent

How can you quickly identify if a bond is Ionic or Covalent?

How can you quickly identify if a bond is Ionic or Covalent?

If it starts with a metal or ammonium, it is ionic. If it starts with a nonmetal, it is covalent.

Determine the number of valence electrons for each of the following atoms.

• Magnesium

• Iodine

• Helium

• Aluminum

Draw the Lewis structure for HCN

Draw the Lewis dot diagram for phosphorus.

Draw the Lewis Structure of CH₃Cl

Draw the Lewis dot diagram of N^3-

Draw the Lewis dot diagram of Mg²⁺

Draw the Lewis dot diagram for magnesium and chlorine when they form a bond.

Draw the Lewis structure for NO₂^-1

Give the name for PbI₂

Give the name for MgCO₃

Give the name for CoO

Give the name for SF₆

Give the name for ClO₂

Write the formula for calcium phosphate

Write the formula for diphosphorus pentoxide

Write the formula for nickel (II) phosphite

Write the formula for lithium permanganate

Write the formula for chromium (III) perchlorate

Write the formula for chromium (III) perchlorate