Question

1. how many protons, electrons, and neutrons are in each of the following isotopes? a. uranium - 235 b. hydrogen - 3 c. silicon - 29

Explanation:

Step1: Recall the atomic number and mass number relationship

The atomic number ($Z$) gives the number of protons. For a neutral atom, the number of electrons equals the number of protons. The mass number ($A$) is the sum of protons ($p$) and neutrons ($n$), so $n=A - Z$.

Step2: Find atomic number of each element

• For uranium ($U$), the atomic number $Z = 92$.
• For hydrogen ($H$), the atomic number $Z = 1$.
• For silicon ($Si$), the atomic number $Z = 14$.

Step3: Calculate for uranium - 235

• Protons: $p=92$ (from atomic number of $U$)
• Electrons: $e = 92$ (neutral atom)
• Neutrons: $n=235 - 92=143$

Step4: Calculate for hydrogen - 3

• Protons: $p = 1$ (from atomic number of $H$)
• Electrons: $e=1$ (neutral atom)
• Neutrons: $n=3 - 1=2$

Step5: Calculate for silicon - 29

• Protons: $p = 14$ (from atomic number of $Si$)
• Electrons: $e = 14$ (neutral atom)
• Neutrons: $n=29 - 14=15$

Answer:

a. Protons: 92, Electrons: 92, Neutrons: 143
b. Protons: 1, Electrons: 1, Neutrons: 2
c. Protons: 14, Electrons: 14, Neutrons: 15