Which of the following changes when a catalyst is used

Enthalpy of reaction

activation energy

both enthalpy of reaction and activation energy change

neither enthalpy of reaction nor activation change

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.