1. Protons: Protons carry a positive electric charge, so the number of protons in an atom or ion determines its positive charge. Each proton contributes a +1 charge.
2. Electrons: Electrons carry a negative electric charge, so the number of electrons in an atom or ion determines its negative charge. Each electron contributes a -1 charge.
3. Neutrons: Neutrons have no electric charge, so they do not contribute to the overall charge of an atom or ion.
To find the net charge of an atom or ion:
1. Count the number of protons: This gives you the total positive charge.
2. Count the number of electrons: This gives you the total negative charge.
3. Subtract the total negative charge from the total positive charge:
- If the result is positive, the atom or ion has a net positive charge (cation).
- If the result is negative, the atom or ion has a net negative charge (anion).
- If the result is zero, the atom or ion has no net charge (neutral).
For example:
1. Neutral atom: Oxygen has 8 protons (8+) and 8 electrons (8-). The net charge is 8+ - 8- = 0, so oxygen is a neutral atom.
2. Positive ion (cation): Sodium ion has 11 protons (11+) and 10 electrons (10-). The net charge is 11+ - 10- = +1, so sodium ion is a cation with a +1 charge.
3. Negative ion (anion): Chloride ion has 17 protons (17+) and 18 electrons (18-). The net charge is 17+ - 18- = -1, so chloride ion is an anion with a -1 charge.
In summary, the charge of an atom or ion is determined by comparing the number of protons (positive charge) to the number of electrons (negative charge). The net charge can be positive, negative, or zero, indicating a cation, anion, or neutral atom, respectively.
