Question

1. choose the best answer based on the lewis structure.

what is the central atom?
(options: hydrogen, oxygen)
(another question: 7. choose the best answer.
which structure has 2 double bonds?
options: sio, si₂o₇²⁻, sio₂, si₃o₇²⁻)

Explanation:

1. For the first question: In the Lewis structure of water ($H_2O$), the central atom is the one bonded to multiple other atoms. Oxygen is bonded to two hydrogen atoms, so it is the central atom.
2. For the second question: In $SiO_2$, each silicon atom forms two double covalent bonds with oxygen atoms, resulting in a total of 2 double bonds per silicon center in the molecular structure. The other silicon oxide structures do not have this bonding configuration.

Answer:

1. oxygen
2. $SiO_2$