Question

how many electrons, protons, and neutrons are in an atom of $_{45}^{67}x$?
a 45 electrons, 45 protons, 22 neutrons.
b 67 electrons, 67 protons, 45 neutrons.
c 67 electrons, 45 protons, 22 neutrons.
d 22 electrons, 89 protons, 45 neutrons.

Explanation:

Step1: Recall the relationship between atomic number, mass number, electrons, protons and neutrons

In an atom, the atomic number \(Z\) (subscript) is equal to the number of protons and also equal to the number of electrons (for a neutral atom). The mass number \(A\) (superscript) is equal to the sum of the number of protons (\(p\)) and neutrons (\(n\)), i.e., \(A=p + n\).
For the atom \(^{67}_{45}X\), the atomic number \(Z = 45\) and the mass number \(A=67\).

Step2: Calculate the number of electrons, protons and neutrons

• Number of electrons (\(e\)): Since \(e=p\) (for a neutral atom) and \(Z = p\), \(e = 45\)
• Number of protons (\(p\)): \(p=Z = 45\)
• Number of neutrons (\(n\)): Using the formula \(A=p + n\), we can solve for \(n\). Substitute \(A = 67\) and \(p = 45\) into the formula: \(n=A - p=67 - 45=22\)

Answer:

a. 45 electrons, 45 protons, 22 neutrons.