Which of the following compounds has an atom with an unfilled valence shell of electrons?
A) H3O+
B) BF3
C) CH3OH
D) NaI
Why not draw the Lewis dot structure and see which one is not complete? Try drawing the Lewis structure for BF3 and see what you get.
Boron is one of the exceptions, correct?
It has 6 valence electrons.
yes
To determine which of the given compounds has an atom with an unfilled valence shell of electrons, we need to look at the electronic configuration of each atom involved.
A) H3O+:
The central atom is O (oxygen) in this compound. Oxygen has 6 valence electrons (group 16), and in this case, it has formed three covalent bonds with three hydrogen atoms. Thus, the valence shell of oxygen in H3O+ is filled with 8 electrons (2 electrons from each bond and 2 lone pairs).
B) BF3:
The central atom is B (boron) in this compound. Boron has 3 valence electrons (group 13), and in this case, it has formed three covalent bonds with three fluorine atoms. Boron is surrounded by 6 electrons (2 electrons from each bond), meaning it has an unfilled valence shell. Therefore, BF3 has an atom with an unfilled valence shell.
C) CH3OH:
The central atom is C (carbon) in this compound. Carbon has 4 valence electrons (group 14), and in this case, it has formed covalent bonds with 3 hydrogen atoms and 1 oxygen atom. Carbon is surrounded by 8 electrons (4 electrons from the bonds), so its valence shell is filled.
D) NaI:
This compound consists of an ionic bond between sodium (Na) and iodine (I). Sodium has 1 valence electron (group 1), and iodine has 7 valence electrons (group 17). Sodium transfers its electron to iodine, resulting in sodium having a filled valence shell, and iodine having an unfilled valence shell.
So, the compound in which an atom has an unfilled valence shell of electrons is B) BF3.