Final answer:
The six basic steps in writing a Lewis structure include counting valence electrons, choosing the least electronegative atom as the central atom, and sharing electrons to complete octets for each atom involved.
Step-by-step explanation:
Steps to Writing Lewis Structures
To correctly answer the student's question, the six basic steps used in writing the Lewis structure are as follows:
- Determine the total number of valence electrons in the molecule or ion. For cations, subtract one electron for each positive charge. For anions, add one electron for each negative charge.
- Draw a skeleton structure of the molecule or ion, arranging the atoms around a central atom. Generally, the least electronegative atom should be placed in the center. Connect each atom to the central atom with a single bond (one electron pair).
- Distribute the remaining electrons as lone pairs on the terminal atoms (except hydrogen), completing an octet around each atom.
- Place a bonding pair of electrons between each pair of adjacent atoms to give a single bond. For example, in H₂O, bonding pairs of electrons are shared between oxygen and each hydrogen.
- Beginning with the terminal atoms, add enough electrons to give each atom an octet (two for hydrogen). These electrons will often be in the form of lone pairs.
- If the central atom does not have an octet, form multiple bonds (double or triple) with the terminal atoms to complete the octet.
Therefore, the correct answer is (a) Count total valence electrons, place least electronegative atom in the center, and share electrons to complete octets.