Phosphate Ion and Lewis Structures

The video tutorial covers Lewis structures and exceptions to the octet rule, including molecules with odd numbers of electrons, less than an octet, and expanded octets. It provides examples like nitrogen monoxide, beryllium dichloride, and the phosphate ion, explaining how to calculate formal charges and identify resonance structures. The tutorial emphasizes the importance of electronegativity in determining the stability of Lewis structures.

What is a common characteristic of molecules with an odd number of electrons?

• They are generally stable.

• They are highly reactive.

• They always follow the octet rule.

• They have an even number of valence electrons.

Which elements are most likely to form molecules with less than an octet?

• Oxygen and fluorine

• Carbon and nitrogen

• Beryllium and boron

• Phosphorus and sulfur

Why can elements in the third period have more than eight valence electrons?

• They have access to 3d orbitals.

• They are larger in size.

• They have higher electronegativity.

• They are more reactive.

In the example of beryllium dichloride, why is the first Lewis structure considered correct?

• Beryllium has a full octet.

• The formal charges are closest to zero.

• It has the least number of electrons.

• It has the most bonds.

What is the formal charge on beryllium in the correct Lewis structure of BeCl2?

• +1

• 0

• -1

• -2

How many valence electrons does the phosphate ion (PO4 3-) have?

• 24

• 36

• 28

• 32

What is the formal charge on phosphorus in the most stable Lewis structure of the phosphate ion?

• +1

• -2

• 0

• -1

How many resonance structures does the phosphate ion have?

• 6

• 3

• 4

• 5

Why is the Lewis structure with a double bond to phosphorus more stable for the phosphate ion?

• It has fewer electrons.

• It has more resonance structures.

• It has formal charges closer to zero.

• It follows the octet rule strictly.

In the phosphate ion, which atom typically carries a negative formal charge?

• Nitrogen

• Oxygen

• Phosphorus

• Hydrogen