# An isotope of U-235 has 92 protons in its nucleus. How many neutrons are there in the nucleus of a U-238 isotope?

May 22, 2018

There are $238 - 92 = 146 \cdot \text{neutrons....}$

#### Explanation:

We are given that ${Z}_{\text{uranium}} = 92$...because this is the number of protons, massive, positively charged particles present ion the uranium nucleus. $Z = \text{the atomic number}$ and it DEFINES the identity of the nucleus.

The nucleus can also contain neutrons...massive, NEUTRALLY charged particles. Interactions between protons and neutrons result in the strong nuclear force, AN ATTRACTIVE force, the which at SHORT nuclear ranges is strong enuff to dominate the electrostatic force of REPULSION associated with the like-charged protons.

Together, the massive, nuclear particles, protons and neutrons DEFINE the atomic mass....

How many neutrons in ""^235U?