In your own words described what a delocalized electron is in its importance to metallic bonding

Delocalized electrons are not associated with a particular nucleus of metal, instead, they are free to move throughout the whole crystalline structure forming a "sea" of electrons. The electrons and the positive ions in the metal have a strong attractive force between them.

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.