Question

The element lead (Pb) consists of four naturally occurring isotopes with atomic masses 203.97302,205.97444,206.97587, and 207.97663 amu. The relative abundances of these four isotopes are 1.4,24.1,22.1, and 52.4 %, respectively. From these data, calculate the atomic weight of lead.

Answer 1

The atomic weight of lead is 207.2169 amu

Step-by-step explanation:

Step 1: Data given

Lead has 4 isotopes:

⇒ 203.97302 = 1.4 %

⇒ 205.97444 = 24.1 %

⇒ 206.97587 = 22.1 %

⇒ 207.97663 = 52.4 %

Step 2: Calculate the atomic weight of lead

Atomic weight = 203.97302 * 0.014 + 205.97444*0.241 + 206.97587 *0.221 + 207.97663 * 0.524

Atomic weight = 207.21688371 ≈ 207.2169 amu

The atomic weight of lead is 207.2169 amu