using VSEPR THEORY SHOW 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 molecule

See your post above.

To determine the molecular geometry of a molecule using VSEPR (Valence Shell Electron Pair Repulsion) theory, you need to follow a few steps:

1) Determine the central atom: Identify the atom that forms the central core of the molecule. It is typically the least electronegative atom or the one that has the highest valence to form multiple bonds.

2) Calculate the total number of valence electrons: Sum up the valence electrons of all atoms in the molecule.

3) Determine the Lewis structure: Connect the atoms using single bonds and place any remaining electrons around the atoms to satisfy octet or duet rules. Remember to prioritize multiple bonds over single bonds when forming the Lewis structure.

4) Count the bonding and non-bonding electron pairs: Identify the regions around the central atom where electrons are localized. These regions can consist of either bonding pairs (electrons shared between atoms) or non-bonding pairs (lone pairs placed around the central atom).

5) Predict the molecular geometry: Use the number of bonding and non-bonding electron pairs to determine the arrangement of these regions around the central atom. VSEPR theory approximates that electron pairs repel each other and will arrange themselves in a manner that minimizes repulsion.

Now, let's apply these steps to the provided molecules:

1) BF4-:
- The central atom is B (boron).
- Calculate the total number of valence electrons: Boron contributes 3 valence electrons, and each fluorine contributes 7 valence electrons (4 fluorines in total). So, the total is 3 + (7 × 4) + 1 (negative charge from BF4-) = 32 valence electrons.
- Count the bonding and non-bonding electron pairs: There are four bonding pairs (B-F bonds), making eight electrons, and no non-bonding pairs.
- Predict the molecular geometry: With four bonding pairs, the electron pairs arrange themselves around the central atom in a tetrahedral shape.

2) SF3+:
- The central atom is S (sulfur).
- Calculate the total number of valence electrons: Sulfur contributes 6 valence electrons, and each fluorine contributes 7 valence electrons (3 fluorines in total). So, the total is 6 + (7 × 3) - 1 (positive charge from SF3+) = 24 valence electrons.
- Count the bonding and non-bonding electron pairs: There are three bonding pairs (S-F bonds), making six electrons, and one non-bonding pair.
- Predict the molecular geometry: With three bonding pairs and one non-bonding pair, the electron pairs arrange themselves around the central atom in a trigonal pyramidal shape.

3) ICl4-:
- The central atom is I (iodine).
- Calculate the total number of valence electrons: Iodine contributes 7 valence electrons, and each chlorine contributes 7 valence electrons (4 chlorines in total). So, the total is 7 + (7 × 4) + 1 (negative charge from ICl4-) = 36 valence electrons.
- Count the bonding and non-bonding electron pairs: There are four bonding pairs (I-Cl bonds), making eight electrons, and no non-bonding pairs.
- Predict the molecular geometry: With four bonding pairs, the electron pairs arrange themselves around the central atom in a square planar shape.

4) IF5:
- The central atom is I (iodine).
- Calculate the total number of valence electrons: Iodine contributes 7 valence electrons, and each fluorine contributes 7 valence electrons (5 fluorines in total). So, the total is 7 + (7 × 5) = 42 valence electrons.
- Count the bonding and non-bonding electron pairs: There are five bonding pairs (I-F bonds), making ten electrons, and no non-bonding pairs.
- Predict the molecular geometry: With five bonding pairs, the electron pairs arrange themselves around the central atom in a square pyramidal shape.

5) PF5:
- The central atom is P (phosphorus).
- Calculate the total number of valence electrons: Phosphorus contributes 5 valence electrons, and each fluorine contributes 7 valence electrons (5 fluorines in total). So, the total is 5 + (7 × 5) = 40 valence electrons.
- Count the bonding and non-bonding electron pairs: There are five bonding pairs (P-F bonds), making ten electrons, and no non-bonding pairs.
- Predict the molecular geometry: With five bonding pairs, the electron pairs arrange themselves around the central atom in a trigonal bipyramidal shape.

Remember, these predicted molecular geometries are based on the VSEPR theory, which considers electron repulsion. However, in some cases, certain factors like lone pairs' influence can distort the predicted geometry.