Help, please this is a science task, and I need to explain what’s the difference between expansion and contraction (please don’t paste the answers your gonna put here) (it has to be your own words) the first person to help me will get)

that tool would be a compass

ca has a crystalline lattice with positive ions (since it is a metal, metals are positively charged) and electrons flow freely in its structure since the ca atoms have a large nuclear radius so the electrons are not tightly held, therefore the electrons can flow freely since they are not being highly attracted by the nucleus. moreover, one of the properties of metals are that they are conductors of electricity, thus proving ca is the element.