Understanding Formula Units and Bonds

The video tutorial explains the differences between molecules and formula units. Molecules are formed by covalent bonds between non-metals, sharing electrons, while formula units are part of ionic compounds, consisting of metals and non-metals with positive and negative ions. The video illustrates these concepts using examples like NaCl and MgI2, highlighting the fixed ratios in crystal lattices.

What is the primary difference between a molecule and a formula unit?

• Molecules exist in crystal lattices, while formula units exist independently.

• Molecules are always charged, while formula units are neutral.

• Molecules have covalent bonds, while formula units have ionic bonds.

• Molecules are made of metals, while formula units are made of non-metals.

In a covalent bond, what happens to the electrons?

• They are transferred from one atom to another.

• They are lost to the environment.

• They are shared between atoms.

• They are absorbed by a single atom.

What type of bond is found in a formula unit?

• Metallic bond

• Ionic bond

• Hydrogen bond

• Covalent bond

Why do formula units not exist independently?

• They are unstable in isolation.

• They require a liquid medium to exist.

• They are always part of a larger crystal lattice.

• They are too small to exist alone.

What is the fixed ratio of ions in NaCl?

• 1:2

• 2:1

• 3:1

• 1:1

In the formula unit MgI2, how many iodide ions are there for each magnesium ion?

• One

• Two

• Three

• Four

What is the significance of the fixed ratio in formula units?

• It changes the compound's solubility in water.

• It affects the melting point of the compound.

• It ensures the stability of the crystal lattice.

• It determines the color of the compound.