Question

What are the characteristics of a molecule

Answer 1

Answer:

All molecules have a definite mass and size that are dependent on the atoms from which the molecule is made. The mass is equal to the sum of the masses of all the individual atoms in the molecular structure....................

Explanation:

,...........................

Answer 2

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Characteristics of molecules

Unlike the ions in ionic compounds, which are arranged in lattices called crystals, molecules of covalent compounds exist as discrete units with a characteristic mass and a certain three-dimensional shape.

Molecular Mass

The mass of a molecule—the molecular mass (sometimes called the molecular weight)—is simply the sum of the masses of its atoms. As with formula masses, it is important that you keep track of the number of atoms of each element in the molecular formula to obtain the correct molecular mass. (For more information about formula masses, see Chapter 3 "Ionic Bonding and Simple Ionic Compounds", Section 3.5 "Formula Mass".)

Molecular Shape: VSEPR Theory

Unlike ionic compounds, with their extended crystal lattices, covalent molecules are discrete units with specific three-dimensional shapes. The shape of a molecule is determined by the fact that covalent bonds, which are composed of negatively charged electrons, tend to repel one another. This concept is called the valence shell electron pair repulsion (VSEPR) theory. For example, the two covalent bonds in BeCl2 stay as far from each other as possible, ending up 180° apart from each other. The result is a linear molecule:

The three covalent bonds in BF3 repel each other to form 120° angles in a plane, in a shape called trigonal planar:

The molecules BeCl2 and BF3 actually violate the octet rule; however, such exceptions are rare and will not be discussed in this text.