Answer:
Two solid powders are combined and shaken. The substances form a mixture.
Answer:
According to Bohr, the amount of energy needed to move an electron from one zone to another is a fixed, finite amount. ... The electron with its extra packet of energy becomes excited, and promptly moves out of its lower energy level and takes up a position in a higher energy level. This situation is unstable, however.
The answer is A.
A pure substance is pure, so it cannot be separated in most cases.
Answer: An alpha-particle is identical to the nucleus of a normal (atomic mass four) helium atom i.e. a doubly ionised helium atom. Alpha particles (also termed alpha radiation or alpha rays) was the first nuclear radiation to be discovered, beta particles and gamma rays were identified soon after.
