What is the main difference between protons and neutrons?
O Protons have a much smaller mass than neutrons.
O Protons have a much larger volume than neutrons.
Protons have an electrical charge, but neutrons have no charge.
O Protons make up the nucleus, but neutrons orbit around the nucleus.

Protons have a much larger volume than neutrons.

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

aquifers are bounded above and below by impermeable rock. the driving force of groundwater movement in confined aquifers is pressure, rather than gravity.