Which statement describes an element?

20points

A

Elements are the smallest part of an atom.

B

Elements are made of one kind of atom and cannot be broken down into simpler substances.

C

An element can be made up of many different atoms all with different numbers of protons.

D

Elements are made up of protons, neutrons, and electrons.

Elements are substance that can not be broken down into simpler substance by ordinary chemical process

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.

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.