Ion Chemistry Example 2

Follow the full solution, then compare it with the other examples linked below.

Example 2

medium
An unknown ion has 10 electrons, 8 protons, and 8 neutrons. Identify the element, write the ion symbol, and calculate its charge.

Solution

  1. 1
    Atomic number =8= 8 protons ⇒\Rightarrow oxygen (O).
  2. 2
    Charge == protons −- electrons =8−10=−2= 8 - 10 = -2.
  3. 3
    The ion is O2−\text{O}^{2-} (oxide ion).

Answer

O2−\text{O}^{2-}
When an atom gains electrons, it becomes a negatively charged anion. Oxygen gains two electrons to complete its octet, forming the stable oxide ion.

About Ion

An atom or group of atoms that has gained or lost one or more electrons, resulting in a net positive charge (cation) or net negative.

Learn more about Ion →

More Ion Examples

Example 1 easy

Sodium ([formula]) loses one electron. Write the ion formed and its electron configuration.

Example 3 easy

Predict the ion formed by each: (a) calcium, (b) fluorine, (c) aluminum.

Example 4 medium

Aluminum loses 3 electrons. What ion forms, and why is its charge positive?

← All Ion Examples Ion Concept