Valence Electron Chemistry Example 2

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

Example 2

medium
Explain why elements in Group 17 (halogens) are highly reactive, using the concept of valence electrons.

Solution

  1. 1
    Halogens have 7 valence electrons (Group 17).
  2. 2
    They need only 1 more electron to achieve a stable octet (noble gas configuration).
  3. 3
    This strong tendency to gain one electron makes them highly reactive, especially with metals that readily lose electrons.

Answer

7 valence electrons→need 1 more for octet→high reactivity\text{7 valence electrons} \rightarrow \text{need 1 more for octet} \rightarrow \text{high reactivity}
Reactivity is closely tied to how close an atom is to achieving a full valence shell. Halogens are one electron short, making them among the most reactive nonmetals.

About Valence Electron

An electron residing in the outermost (highest-energy) occupied shell of an atom, available for participation in chemical bonding through sharing, gaining, or losing.

Learn more about Valence Electron →

More Valence Electron Examples

Example 1 easy

How many valence electrons does nitrogen ([formula]) have?

Example 3 easy

Determine the number of valence electrons for: (a) carbon, (b) sulfur, (c) argon.

Example 4 medium

Sodium has electron arrangement 2,8,1. How many valence electrons does it have, and is it more likel

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