How many valence electrons are there in a fluorine atom? (b) How many electrons does a fluorine atom need to share to become stable? (c) Draw a sketch to show how two fluorine atoms could form a stable molecule.
The Correct Answer and Explanation is:
(a) Valence Electrons in a Fluorine Atom:
A fluorine atom has 9 electrons in total, and its electron configuration is 1s² 2s² 2p⁵. The electrons in the outermost energy level (n = 2) are called valence electrons, and these are the electrons involved in bonding. Fluorine has 7 valence electrons, as there are 2 electrons in the 2s orbital and 5 electrons in the 2p orbitals.
(b) Electrons Fluorine Needs to Share to Become Stable:
Fluorine has 7 valence electrons but needs 8 electrons to achieve a stable, full outer shell (like the noble gases). Since it already has 7 electrons, it needs to share 1 more electron to complete its octet. This is typical for halogens, which usually form one bond by sharing a single electron.
(c) Sketch of Two Fluorine Atoms Forming a Stable Molecule:
In order to form a stable molecule, two fluorine atoms will share one electron each to complete their octets. Here’s how this looks in a simple diagram:
rCopyEditF : F
- The single bond between the two fluorine atoms represents the sharing of one electron from each fluorine atom.
- Each fluorine atom now has 8 electrons in its valence shell: 7 from its own electrons and 1 from the other fluorine atom.
This creates a stable fluorine molecule (F₂) where both atoms have full outer electron shells, which is the most stable configuration for them. This type of bond is known as a single covalent bond because each fluorine atom shares one electron to form the bond.
