The mass number of an isotope of uranium is 238, and its atomic number is 92. which symbol best represents this isotope of uranium?

The isotope will be represented  by symbol .

Solution:

The isotope of an element is represented by:

X = Symbol of an element

Z = Atomic Number of that element = Total number of electrons or protons

A = atomic mass of that element = Z+ total number of neutrons

So the uranium isotope with atomic mass of 238 and atomic number of 92 will be written as:

a electronegativity decreases beacuse the size of nucleus is bigger.