Question

Compare and contrast these isotopes: uranium -239, uranium -238, and uranium -235

Answer 1

They all have the same number of protons and electrons but differ in the number of neutrons because they are isotopes.

Answer 2

Answer: They have same number of protons but differ in number of neutrons.

Explanation:

Isotopes are defined as the species which have same number of neutrons but differ in the number of neutrons.

Uranium is the 92nd element of the periodic table.

Atomic number is defined as the number of protons that are present in an atom.  

Atomic number = Number of protons

Mass number is defined as the sum of number of protons and neutrons that are present in an atom.

Mass number = Number of protons + Number of neutrons

For the given isotopes:  $_{92}^{239}\textrm{U},_{92}^{238}\textrm{U}\text{ and }_{92}^{235}\textrm{U}$

• For $_{92}^{239}\textrm{U}$

Number of protons = 92

Number of neutrons = 239 - 92 = 147

• For $_{92}^{238}\textrm{U}$

Number of protons = 92

Number of neutrons = 238 - 92 = 146

• For $_{92}^{235}\textrm{U}$

Number of protons = 92

Number of neutrons = 235 - 92 = 143

Hence, they have same number of protons but differ in number of neutrons.