1. (C.) -Si- is silicone which at room temp is a solid and it's a hard crystalline Brittle rock basically...
2. And it will Be D. NOT C... i can't stand user's who throw out answers for free points....
Eight electrons surrounding each non-hydrogen atom is the optimal electronic arrangement for covalent molecules because it is needed to achieve an octet structure and is necessary to fill both the s and p subshells of electrons.
<h3>What is Covalent bonding?</h3>
This is the type of bonding which involves the sharing of electrons between atoms of an element.
This is done to achieve an octet configuration thereby making them stable and less reactive thereby making it the most appropriate choice.
Read more about Covalent bonding here brainly.com/question/3447218
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Answer:
t = 6.17 s
Explanation:
For a 1 revolution movement, 
Torque, 
Moment of Inertia, 
If the wheel starts from rest, 
The angular displacement of the wheel can be given by the formula:
................(1)
Where
is the angular acceleration

To get t, put all necessary parameters into equation (1)
