Elements can combine to form molecules, like o2 or co2. elements combine to form molecules and these elements are joined together by
a. chemical bonds.
b. nuclear energy.
c. sharing nuclei.
d. attractive forces.

a. Chemical bonds.

Explanation:

Hello,

In this case, it is necessary to know that when two elements are not stable by their own they should bond with an other atom of the same element via chemical bonds whereby the valence electrons act as bridges connecting the atoms. Some examples are diatomic-gaseous hydrogen, oxygen, nitrogen, chlorine, iodine, fluorine and bromine. Moreover, such chemical bonding is represented by lines binding the elements as shown on the attached picture.

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the temperature of the gas, in k, not celsius.

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.