What are costal plains?

A coastal plain is flat, low-lying land adjacent to a sea coast. ... The Coastal Plains of India lie on either side of the Peninsular Plateau, along the western and eastern coasts of India.

Heres an image :D

because the two particles have an equal charge, the charges will cancel out and give the atom an overall charge of 0. so, if at atom has 35 protons in the nucleus, we could expect it to have 35 electrons orbiting that nucleus.