Question

how do you calculate or identify the number of: protons= neutrons= electrons=

Explanation:

Protons

Step1: Identify Atomic Number

The number of protons in an atom is equal to its atomic number. For example, hydrogen has an atomic number of \(1\), so it has \(1\) proton.

Neutrons

Step1: Know Mass Number and Atomic Number

The formula to calculate the number of neutrons is \(n = A - Z\), where \(A\) is the mass number and \(Z\) is the atomic number. For instance, if an atom has a mass number \(A = 12\) and atomic number \(Z = 6\) (like carbon - 12), then \(n=12 - 6=6\) neutrons.

Electrons

Step1: For Neutral Atoms

In a neutral atom, the number of electrons is equal to the number of protons (which is equal to the atomic number). For example, a neutral oxygen atom with atomic number \(Z = 8\) has \(8\) electrons.

Step2: For Ions

• Cations (positive ions): If an atom loses \(x\) electrons to form a cation, the number of electrons is \(Z - x\). For example, \(Na^{+}\) (sodium ion), sodium has \(Z = 11\), and since it loses \(1\) electron, the number of electrons is \(11- 1=10\).
• Anions (negative ions): If an atom gains \(y\) electrons to form an anion, the number of electrons is \(Z + y\). For example, \(Cl^{-}\) (chloride ion), chlorine has \(Z = 17\), and since it gains \(1\) electron, the number of electrons is \(17 + 1=18\).

Answer:

• Protons: Equal to the atomic number of the element.
• Neutrons: \(n = A - Z\) (where \(A\) is the mass number and \(Z\) is the atomic number).
• Electrons:
• Neutral atom: Equal to the atomic number (\(Z\)).
• Cation: \(Z - x\) (\(x\) is the number of electrons lost).
• Anion: \(Z + y\) (\(y\) is the number of electrons gained).