Question

Which of the following is a possible formula unit? (2 points) Select one: a. PbO b. Li2B c. Al2Pb3 d. ClO

Answer 1

Answer:

a. PbO.

Explanation:

• The formula unit of a stable chemical compound should maintain that the overall charge of the compound is zero (not charged).

• The formula unit of a compound is represented by the lowest ratio numbers of the ions forming the compound.

Choice a: is the right answer PbO

• That lead is divalent cation Pb²⁺ and O is considered as a divalent anion O²⁻.

• So, the formula unit contains Pb:O with a ratio of 1:1 (PbO)

Choice b: is a wrong choice Li₂B

• The lithium cation is a monovalent cation Li¹⁺ and boron is a trivalent cation B³⁺, so we can not do that.

Choice c: is a wrong choice Al₂Pb₃

• that Al is a trivalent cation Al³⁺ and Pb is a divalent cation Pb²⁺, so we can not do this for the two cations.

Choice d: is a wrong choice ClO

• that Cl may act as Cl¹⁺ and O acts as O²⁻, so the right formula unit should be Cl₂O.