Question

1. calculate the number of protons, neutrons, and electrons for each of the following t/i-4 marks

a) ( ^{35}_{17}\text{cl} )
b) ( ^{40}_{20}\text{ca} )

Explanation:

Part (a): $\boldsymbol{^{35}_{17}\text{Cl}}$

Step 1: Determine Protons

The atomic number (bottom number) is the number of protons. For $\ce{^{35}_{17}Cl}$, atomic number $Z = 17$, so protons $= 17$.

Step 2: Determine Neutrons

Mass number (top number) $A = 35$. Neutrons $= A - Z = 35 - 17 = 18$.

Step 3: Determine Electrons

In a neutral atom, electrons = protons. So electrons $= 17$.

Part (b): $\boldsymbol{^{40}_{20}\text{Ca}}$

Step 1: Determine Protons

Atomic number $Z = 20$, so protons $= 20$.

Step 2: Determine Neutrons

Mass number $A = 40$. Neutrons $= A - Z = 40 - 20 = 20$.

Step 3: Determine Electrons

Neutral atom, so electrons = protons $= 20$.

Answer:

• For $\boldsymbol{^{35}_{17}\text{Cl}}$: Protons = 17, Neutrons = 18, Electrons = 17
• For $\boldsymbol{^{40}_{20}\text{Ca}}$: Protons = 20, Neutrons = 20, Electrons = 20