Based on standard atomic weight definitions and the provided reference, no element has an exact atomic weight of 36. However, if the question intended to ask for the element with an atomic number of 36, that element is Krypton (Kr).
Understanding Atomic Weight vs. Atomic Number
It's crucial to distinguish between atomic weight and atomic number when identifying elements:
- Atomic Number (Z): This fundamental property represents the number of protons within an atom's nucleus. It is a unique identifier for each element. For instance, every atom of Krypton contains 36 protons.
- Atomic Weight (Standard Atomic Weight): This value reflects the weighted average of the atomic masses of all naturally occurring isotopes of an element. Because of the varying masses and natural abundances of isotopes, atomic weight is typically not a whole number.
Element Data Around Atomic Number 36
The following data, ordered by atomic number, helps clarify the elements and their respective atomic weights:
| Atomic No | Symbol | Atomic Weight |
|---|---|---|
| 34 | Se | 78.971(8) |
| 35 | Br | 79.904(3) |
| 36 | Kr | 83.798(2) |
| 37 | Rb | 85.4678(3) |
As illustrated in the table:
- The element with an atomic number of 36 is Krypton (Kr).
- The atomic weight of Krypton is 83.798(2).
Clarification on Atomic Weight 36
An element with a standard atomic weight of exactly 36 does not exist. Atomic weights are rarely whole numbers, and the values for elements with atomic numbers in this range are significantly different. For example, Chlorine (Cl) has a standard atomic weight of approximately 35.45, and Argon (Ar) is about 39.95. While a specific isotope, such as Chlorine-37, has an atomic mass close to 36 (around 36.9659 amu), the question specifically asks for the "atomic weight" of an "element," which refers to the standard atomic weight.
Therefore, if the question strictly refers to an element with an atomic weight of exactly 36, such an element is not found in the provided reference and is not a recognized standard atomic weight for any known element. However, if the intent was to identify the element with an atomic number of 36, the answer is Krypton.
