Which of these statements describes the basic idea of the Valence Shell Electron Pair Repulsion (VSEPR) theory?
1. Molecules repel one another due to intermolecular forces.

2. There is always an octet of electrons around an atom in a molecule

3. Shared and unshared electron pairs repel each other as much as
possible
4. Electrons are attracted to the nucleus of the central atom.

3. Shared and unshared electron pairs repel each other as much as

possible

Explanation:

The variations in the bond angles of molecules and ions can be explained using the valence shell electron pair repulsion theory.

The VESPR model determines the total number of electron pairs (TEP) surrounding the central atom of a specie. The TEP consists of bond pairs BP and lone pairs LP.

All the electron pairs will orient themselves in such a way as to minimize the electrostatic repulsion between them.

The repulsion determines the geometry of the covalent bonds around the central atom. As the number of lone pairs increases from 0 to 2, the bond angles diminishes progressively.

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the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.