You should read up on Proust's law, better known as the Law of Definite Proportions. This is a chemical law that defines your question more generally, on why the ratio of elements and ions are always fixed.
Basically, this compound Magnesium(II) Chloride is MgCl2 because it has the same number of protons, neutrons, and electrons all the way. This defines the properties of the compound or atom.
Answer:
Bohr's model of the hydrogen atom is based on three postulates:
1) An electron moves around the nucleus in a circular orbit,
2) An electron's angular momentum in the orbit is quantised,
3) The change in an electron's energy as it makes a quantum jump from one orbit to another is always accompanied by the emission or absorption of a photon. Bohr's model is semi-classical because it combines the classical concept of electron orbit (postulate 1) with the new concept of quantisation ( postulates 2 and ).
You got the questions correct
At absolute zero the kinetic energy of the substance will be 0
It is photosynthesis
<span>
photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water. photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a byproduct, hope it helps</span>