Answer:
This means that the isotope of silicon with a mass number of 28 is by far the most common of these three isotopes.
Explanation:
The abundance of Si-28 is 92.23%. Si-29 is 4.68% and Si-30 is 3.09%.
Because most Si atoms have a mass of 28 amu, the average mass of all silicon atoms is very close to 28.
Here is a video which summarizes how to calculate average atomic mass from data about mass and relative abundance.
Answer:
think I did this before and its V
Covalent compound as it is a bond between two non-metals
1.it is readily available since hydrogen is a basic earth element and it's very abundant.
2. It doesn't produce harmful emissions.
Disadvantages
1.it is expensive. It is expensive because it takes a lot of time to separate the element from others.
2.it is difficult to store. Even moving a tiny bit of hydrogen would be very expensive.
3. It is highly flammable. Since it is a very powerful source of fuel, hydrogen can be very flammable.