Use the periodic table and what you know about mass numbers to complete each statement.U-238 has protons and146 neutrons.A particular isotope of plutonium has 94 protons, neutrons, and a mass number of 241.Thorium- has 90 protons and 137 neutrons.

Answer 1

Let's break down the information provided and complete the statements regarding the isotopes.

1. U-238 has 92 protons and 146 neutrons. Thus, the mass number of U-238 is the sum of the number of protons and neutrons: \[ \text{Mass number} = \text{Protons} + \text{Neutrons} = 92 + 146 = 238 \] So, U-238 is Uranium-238.

2. A particular isotope of plutonium has 94 protons, neutrons (we need to find this), and a mass number of 241. Using the mass number to find neutrons: \[ \text{Neutrons} = \text{Mass number} - \text{Protons} = 241 - 94 = 147 \] Therefore, this isotope of plutonium is Plutonium-241 (Pu-241), which has 94 protons and 147 neutrons.

3. Thorium- (we need to find the mass number) has 90 protons and 137 neutrons. Calculating the mass number: \[ \text{Mass number} = \text{Protons} + \text{Neutrons} = 90 + 137 = 227 \] Thus, this isotope of thorium is Thorium-227 (Th-227).

Here are the complete statements:

• U-238 has 92 protons and 146 neutrons.
• A particular isotope of plutonium has 94 protons, 147 neutrons, and a mass number of 241.
• Thorium-227 has 90 protons and 137 neutrons.