Humans started using elemental copper about 6000 years ago and started using elemental tin about 3800 years ago. use the heat of formation values for copper c (ii) oxide and tin (iv) oxide to explain why humans were able to use elemental copper before they were able to use elemental tin.

As the Tin has "lousy properties," humans can use copper before tin.

Explanation:

Heat of formation of the copper (II) oxide = -156KJ/mol

Heat of formation of Tin (IV) oxide =-581KJ/mol

As, we know that the copper will form the copper oxide after receiving reduced energy. Humans were able to use the elemental copper before tin. And also, tin has itself the lousy properties as compared to Copper. Copper are also the good conductor of heat, hence they are used in the electric wiring. Apart, from that it is also being used for roofing and plumbing. And as heat exchangers in the industries Copper also possess the antibacterial property.

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be