Most elements have several stables but some such as lithium, boron, and copper have 2. consider one such element (it doesn't matter which one). if the abundance of one isotope is 0.1266 what is the abundance of the other isotope?

See below.

Step-by-step explanation:

OK, let's consider lithium. It consists of 7.59 % ⁶Li and 92.41 % ⁷Li and has an atomic mass of 6.94 u.

The atomic mass of ⁶Li is 6.015 u, and that of ⁷Li is 7.016 u.

What would the atomic mass of lithium be if it consisted of 87.34 % ⁶Li and 12.66 % ⁷Li?

The atomic mass of X is the weighted average of the atomic masses of its isotopes.

We multiply the atomic mass of each isotope by a number representing its relative importance (e.g., its fraction of the total).

Set up a table for easy calculation

0.8734 × 6.015 u = 5.254   u

0.1266 × 7.016 u = 0.8882 u

              TOTAL =  6.142    u

The atomic mass of lithium would be 6.14 u instead of 6.94 u.

the correct answer is b. a strong acid completely dissociates to its ions when dissolved in water. completely dissociates to and ions. a is incorrect because does not fully ionize to and ions and some remain as the compound . c and d are incorrect because, and do not fall into the category of bronsted lowry acids. a bronsted lowry acid is a proton donor and since both molecules do not have a proton to donate they are not bronsted lowry acids. likewise,   if we use the lewis acid definition, they cannot be acids. a lewis acid is an electron pair acceptor. both and have a complete octet so can not accept any electrons which disqualifies them as acids.

the answer is option a.