Answer:
Mass: 981.0 g
Density: 5.61 g/cm^3
Hardness: = 2.5 - 3
Unknown material: Chalcocite
Explanation:
The two theories were:
1.Geocentric theory stating that earth is the centre of the universe and sun revolves around it.
2.Heliocentric theory stating that the earth revolves around the sun.
A better explanation of these systems is given using molecular orbital theory.
<h3>What is the valence bond theory?</h3>
The valence bond theory hold that a bond is formed by the sharing of two electron in a covalent bond. This bond does not account for certain systems that occur in multiple bonded systems where the simple two electron bonding model does not suffice.
Thus, valence bond theory is inadequate for describing systems with multiple adjacent bonds that overlap, as in aromatic molecules. a better explanation of these systems is given using molecular orbital theory.
Learn more about valence bond theory:brainly.com/question/23129240
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