Although flame tests are usually specific for each element, they can be misleading. Sodium may be present in each sample therefore a cobalt glass is needed to observe the real color emitted by potassium. Why is blue cobalt glass used instead of any other colored glass?

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.

5.6⋅10−^19  j

do you need the explaination?