Question

The average atomic mass of an element is 39.95 amu. What is the identity of the element? 1. Potassium 2. Yttrium 3. Argon 4. Calcium Enter the answer choice number.

Answer 1

The identity of the element is Argon.

Step-by-step explanation:

The average atomic mass of an element is calculated by taking into account the masses and relative percentages of its isotopes. The weighted average atomic mass is usually close to the mass number of the most abundant isotope. By comparing the given choices to the average atomic mass of 39.95 amu, we can determine the identity of the element.

1. Potassium - The atomic mass of potassium is approximately 39.10 amu, which is not close to 39.95 amu.
2. Yttrium - The atomic mass of yttrium is approximately 88.91 amu, which is not close to 39.95 amu.
3. Argon - The atomic mass of argon is approximately 39.95 amu, which is equal to the given average atomic mass. Therefore, the identity of the element is Argon.
4. Calcium - The atomic mass of calcium is approximately 40.08 amu, which is not close to 39.95 amu.

Answer 2

3. Argon

Step-by-step explanation:

The average atomic mass of an element with a value of 39.95 amu is Argon (Ar). The answer choice number is 3.