Question

1. an isotope has an atomic number 51 and a mass number 123. how many protons, neutrons and electrons does it have if its neutral?

Explanation:

Step1: Find the number of protons

The atomic number \(Z\) is equal to the number of protons. Given \(Z = 51\), so the number of protons \(p=51\).

Step2: Find the number of electrons

For a neutral atom, the number of electrons \(e\) is equal to the number of protons. So \(e = 51\).

Step3: Find the number of neutrons

The mass number \(A\) is given by \(A=p + n\) (where \(n\) is the number of neutrons). Rearranging for \(n\), we get \(n=A - p\). Given \(A = 123\) and \(p = 51\), then \(n=123-51=72\).

Answer:

Protons: \(51\), Neutrons: \(72\), Electrons: \(51\)