Full tablet Reaction time = 34.5 sec
Reaction rate = mg/L/sec
Eight pieces Reaction time = 28.9 sec
Reaction rate = mg/L/sec
Tiny pieces Reaction time = 23.1 sec
Reaction rate = mg/L/sec

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.

im doing test rn im going with 2 but ill give answer if itss wrong,   : )