(Please Help) 1.What is the most common isotope for element X

2.Calculate the average atomic mass or element X

1. Isotope 2 occurs most commonly

2. 39.02amu

Explanation:

1. Isotope 2 has a relative abundance of 78.68% i.e. 78.68 out of 100, hence, it is the isotope that occurs most commonly.

2. Isotope 1 = 9.67%, mass no: 38

Isotope 2 = 78.68%, mass no: 39

Isotope 3 = 11.34%, mass no: 40

Isotope 4 = 0.31%, mass no: 41

To find the average atomic mass of element X, we multiply each isotopes' relative abundance by its mass no and find the sum as follows:

We convert each percentage to decimal abundance:

Isotope 1 = 9.67% = 0.0967

Isotope 2 = 78.68% = 0.7868

Isotope 3 = 11.34% = 0.1134

Isotope 4 = 0.31% = 0.0031

(0.0967 × 38) + (0.7868 × 39) + (0.1134 × 40) + (0.0031 × 41)

3.6746 + 30.6852 + 4.536 + 0.1271

Average atomic mass = 39.02amu

more info ? ? i don't understand what the question is

explanation: