Answer:
He developed the concept of concentric electron energy levels
Explanation:
Before Bohr's model, Rutherford's model was proposed. This model explains most of the properties of the atom but failed to explain the stability of the atom.
As per Rutherford's model, electrons revolve around the nucleus in the orbit.
But revolving electron in their orbit around nucleus would give up energy and so gradually move towards the nucleus and therefore, eventually collapse.
Bohr's proposed that the electrons around the nucleus move orbit of fixed energy called "stationary states". Electrons in these stationary states do not radiate energy.
Therefore, proposal of concentric electron energy levels refine the atomic models.
Answer:
option b is the correct answer
Answer:
396811.337 J
Explanation:
The cost of one short ton of coal = $56.45
The energy related to the short ton of coal = 
Thus, As according to the question,
$56.45 of coal have of energy.
$1 of coal have 
of energy.
<u>The amount of energy = 396811.337 J</u>
Answer: salt
Explanation:
Arrhenius acids are substances which dissociate in water to give 
ions.
Arrhenius bases are substances which dissociate in water to give 
ions.
Thus when they combine, they neutralize each other and produce salt and water.
Answer:
A lunar eclipse occurs when the Moon passes directly behind Earth and into its shadow. This can occur only when the Sun, Earth, and Moon are exactly or very closely aligned (in syzygy), with Earth between the other two. A lunar eclipse can occur only on the night of a full moon.
Explanation:
