Question

determine the number of neutrons, protons, and electrons for a bromide ion that has a mass - number of 77, and a charge of - 1. number of neutrons: number of protons: number of electrons: determine the element symbol, number of protons, and number of electrons for an ion that has a mass number of 56, 30 neutrons, and a charge of + 3. element symbol: number of protons: number of electrons:

Explanation:

Step1: Recall atomic number of bromine

Bromine (Br) has an atomic number of 35. The atomic number is equal to the number of protons. So for the bromide ion, the number of protons $p = 35$.

Step2: Calculate number of neutrons

The mass - number $A$ is given by the sum of protons and neutrons ($A=p + n$). Given $A = 77$ and $p = 35$, we can find the number of neutrons $n$ as $n=A - p$. So $n=77 - 35=42$.

Step3: Calculate number of electrons

The charge of the bromide ion is - 1. For a negatively - charged ion, the number of electrons $e$ is related to the number of protons by $e=p+| \text{charge}|$. So $e = 35+1 = 36$.

Step4: For the second ion

Given mass number $A = 56$ and number of neutrons $n = 30$. Using $A=p + n$, we find the number of protons $p=A - n=56 - 30 = 26$. The element with atomic number 26 is iron, symbol Fe.

Step5: Calculate number of electrons for the second ion

The charge of the ion is + 3. For a positively - charged ion, the number of electrons $e=p-\text{charge}$. So $e = 26-3=23$.

Answer:

number of neutrons (bromide ion): 42
number of protons (bromide ion): 35
number of electrons (bromide ion): 36
element symbol (second ion): Fe
number of protons (second ion): 26
number of electrons (second ion): 23