Why is elemental zinc considered a pure substance?

Zinc is made of only one type of atoms.

Explanation:

Because Zinc is made of only one type of atom this makes it a pure substance.

So Zinc is a pure element which is made of only one type of atom element.

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.