1. PbO is a possible formula units, since O has charge of 2- and Pb can have a charge of 2+ or 4+, if it uses the 2+ ion, the charges will balance out to form PbO. Li+ and B(3-) would have Li3B, Al(3+) and Pb(2+) are both positive charges and would not balance out, Cl- and O(2-) are both negative charges and would not balance out.
2. Iodine is a halogen, so it has a charge of -1. Calcium is an alkaline earth metal in Group 2, so it has a charge of 2+. Therefore, if they were to form a formula unit, the resultant would be CaI2 (2 iodine atoms of 1- charge are needed to balance out the 2+ charge on the calcium atom).
3. Strontium is an alkaline earth metal with a charge of 2+, while phosphorus has a charge of 3-. Therefore, to balance the charges out, we would need 3 atoms of strontium and 2 atoms of phosphorus. This would give the formula unit of Sr3P2.
<u>ANSWER:</u>
When a supergiant runs out of fuel, the object formed is either a black hole or a neutron star.
<u>EXPLANATION:</u>
- Supergiant are very large stars in the galaxy that end their lives very quickly.
- When a supergiant star loses its fuel, it blows itself by a supernove explosion.
- When supernove explosion happens, the supernova outshines other stars in the galaxy and then slowly faded away leaving a dense object called black hole or neutron star.
- This black hole or neutron star is surrounded by a mass of very hot gas and the elements of the supergiant star get scattered into the space.
Answer: D. The succession of community is completed.
Explanation:
A succession can be define as a series of gradual changes that occur in the biotic community of the ecosystem with respect to the changes that occur in the abiotic or non-living factors with respect to time until the ecosystem attains stability.
A climax community is the community that develops in the end of the ecological succession. It is the stable community which does not require any further change to occur. With the development of the climax community the succession completes.
Answer:
B. to understand the world around us
Explanation:
