Carbon can make four bonds. Since it is doubly bonded carbon, it means it can make two more bonds. So, two more hydrogen atoms could help in bond formation.

Two H atoms are attached to each carbon.
The difference would be that Mercury has a denser, warmer atmosphere and Earth has a not that dense and gassy atmosphere. The Earth's atmosphere also has a lot of layers while Mercury's doesn't. Those would be the reasons for them both being different. Hope this helped!
Answer:
<h2>Density = 0.2 g/mL</h2>
Explanation:
The density of a substance can be found by using the formula
<h3>

</h3>
From the question the points are
mass = 6.8 g
volume = 34 mL
Substitute the values into the above formula and solve
That's
<h3>

</h3>
We have the final answer as
<h3>Density = 0.2 g/mL</h3>
Hope this helps you
1. A. All the elements in the column have similar chemical properties.
2. Substances on the periodic table cannot be broken down into other substances and are therefore elements.