Methane geometric shape

Observing and Inferring Describe the geometric shape of the methane model when it is wrapped with aluminum foil. 

Water is known to have the geometric shape known as bent or V-shaped. Carbon dioxide exhibits a linear shape. BF3 forms a third molecular shape called trigonal planar since all the atoms lie in one plane in a triangular arrangement. One of the more common molecular shapes is the tetrahedron, illustrated by the molecule methane (CH4). 

The theoretical basis for a molecule possessing a particular geometric shape is the concept that electron pairs, whether they are part of a covalent bond (as in a bonding pair) or not (as in a nonbonding pair), will repel each other. In methane, water, and all other molecules, this repulsion means that the electron pairs will get as far away from each other as they can get. The general name for this theory is the valence-shell electron-pair repulsion (VSEPR) theory. 

Some illustrative examples are shown above. Despite his disclaimer Kekule s structural formulae are clearly the harbingers of their modern equivalents. The proposed tetrahedral structure of carbon, which followed, ignored the good advice and amounts to no more than a geometrical rearrangement of Kekule s diagrams, as shown here to represent the actual size and shape of carbon in methane. 

The rules and principles of molecular geometry accurately predict the shapes of simple molecules such as methane (CH4), water (H2O), or ammonia (NH3). As molecules become increasingly complex, however, it becomes very difficult, but not impossible, to predict and describe complex geometric arrangements of atoms. The number of bonds between atoms, the types of bonds, and the presence of lone electron pairs on the central atom in the molecule critically influence the arrangement of atoms in a molecule. In addition, use of valance shell electron pair repulsion theory (VSEPR) allows chemists to predict the shape of a molecule. 

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