One question that scientists tried to answer for many years dealt with planetary motion. How did they go about trying to determine the orbits of the planets? What were some of the models that were developed? What were the contributions of the various scientists discussed in the unit to our understandings of this topic?​

he would use the colour black

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.