using VSEPR THEORY explain why
1)BF4- is a tetrahedral molecule
2)SF3+ is a Trigonal pyramidal molecule
3)ICI4- IS A SQUARE PLANER molecule
4IF5 IS A SQUARE pyramidal molecule
5)PF5 IS A TRIGNAL BIPYRAMIDAl
1) To determine the molecular shape of BF4-, we apply the VSEPR (Valence Shell Electron Pair Repulsion) theory.
The formula BF4- indicates that it is an anion, meaning it has an extra electron compared to a neutral molecule.
Beryllium (Be) is the central atom, and it forms four bonds, one with each of the four fluorine (F) atoms. Fluorine is in group 7 of the periodic table with 7 valence electrons, and since it forms a single bond with beryllium, each fluorine atom contributes one electron to the bonding. Additionally, beryllium brings two valence electrons, resulting in a total of 32 valence electrons (4 x 7 + 2 = 30).
According to VSEPR theory, in order to minimize electron repulsion, the valence electron pairs (both bonding and non-bonding) will arrange themselves as far apart as possible around the central atom. In the case of BF4-, there are no lone pairs present, only bonding pairs.
Since there are four bonding pairs, they arrange themselves in a tetrahedral geometry, where the fluorine atoms are situated at the four vertices of a tetrahedron surrounding the beryllium atom.
2) SF3+ is a cation, meaning it has one fewer electron compared to a neutral molecule.
The central atom, sulfur (S), brings six valence electrons. Fluorine (F) is highly electronegative and forms three bonds with the sulfur atom. Each fluorine contributes one valence electron, resulting in a total of 7 valence electrons (3 x 7 + 6 = 27).
To determine the molecular shape of SF3+, we apply the VSEPR theory. Since there is one fewer electron, there will be a vacant spot where the missing electron would have been. This vacant spot results in less electron repulsion, causing the three fluorine atoms to move closer together.
The repulsion between the three fluorine atoms pushes them slightly downward, creating a trigonal pyramidal geometry with the sulfur atom at the center of the base and the fluorine atoms forming an equilateral triangle around it.
3) ICl4- is an anion, meaning it has one additional electron compared to a neutral molecule.
The central atom, iodine (I), brings seven valence electrons. Chlorine (Cl) atoms are highly electronegative and form four bonds with the iodine atom. Each chlorine contributes one valence electron, resulting in a total of 28 valence electrons (4 x 7 + 1 = 29).
Applying the VSEPR theory, we find that ICl4- has four bonding pairs and one lone pair of electrons on the central iodine atom.
To minimize electron repulsion, the bonding pairs arrange themselves in a plane, resulting in a square planar molecular shape. The four chlorine atoms are positioned at the four corners of a square, while the lone pair occupies the remaining position above or below the plane.
4) IF5 is a neutral molecule.
The central atom, iodine (I), brings seven valence electrons. Fluorine (F) atoms are highly electronegative and form five bonds with the iodine atom. Each fluorine contributes one valence electron, resulting in a total of 42 valence electrons (5 x 7 = 35).
Applying the VSEPR theory, we find that IF5 has five bonding pairs and one non-bonding lone pair of electrons on the central iodine atom.
To minimize electron repulsion, the bonding pairs arrange themselves in a square plane, and the lone pair occupies one of the corners, creating a square pyramidal molecular shape.
5) PF5 is a neutral molecule.
The central atom, phosphorus (P), brings five valence electrons. Fluorine (F) atoms are highly electronegative and form five bonds with the phosphorus atom. Each fluorine contributes one valence electron, resulting in a total of 40 valence electrons (5 x 7 = 35).
Applying the VSEPR theory, we find that PF5 has five bonding pairs and no lone pairs of electrons on the central phosphorus atom.
To minimize electron repulsion, the bonding pairs arrange themselves in a trigonal bipyramidal geometry. The three fluorine atoms occupy the equatorial positions, forming an equilateral triangle around the central phosphorus atom. The remaining two fluorine atoms occupy the axial positions, situated above and below the equatorial plane.