The central nitrogen atom in the no2- ion has nonbonded electron pairs and bonded electron pairs in its valence shell.

1 pair of nonbonded electrons

3 pairs of bonded electrons

Explanation:

N has 5 electrons in its valence shell while O has 6.

Lewis structure of NO²⁻ is in the image.

N is in the middle of the structure because is the less electronegative atom. 3 electrons of this atom are forming the bonds and 2 electrons are nonbonded.

As you can see, N has 3 pairs of electrons forming 3 bonds with Oxygens and there is 1 pair of nonbonded electrons.

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation: