Answer:
A neutral particle made of an electron and hole
Explanation:
Exciton
It is the combination of an electron and a hole ( hole refers to the vacancy of an electron ) . And , as both the electron and the hole have the same charge but the polarity is opposite , the combination will lead to a neutral compound , i.e. , Exciton have no charge and so neutral .
It is free to move in the nonmetallic crystal and since it charge less , it is difficult to detect it directly .
Answer:
One mole of carbon would look like 25/12.01
Explanation:
Firstly, you will divide 25 by 12.01 and get 2.081598
We know 1 mole equals the gram per atomic mass, so one mole of carbon is 12.01 grams. In conclusion, it would look like 25/12.01.
1 mol of Br = 79.9 g
15.7 g / 79.9 g = 0.196 moles of atoms
<span>nuclear symbol consists of three parts: 1. the symbol of the
element; 2. the atomic number of the element;3. the mass of the element. for
the above problem, the symbol for potassium is k. it's atomic number is 40. the
number of protons is 19. so we denote this in the following nuclear symbol; 40
k 19</span>
Because at atmospheric pressure the boiling point is below room temperature, just like Oxygen, Nitrogen etc
