Answer: Option (a) is the correct answer.
Explanation:
Atomic number is the sum of only total number of protons present in an element. Whereas mass number is the sum of total number of both protons and neutrons present in an element.
For example, given atom has mass number as 15 and its atomic number is 7.
Therefore, number of neutrons present in it will be calculated as follows.
Mass number = no. of protons + no. of neutrons
15 = 7 + no. of neutrons
no. of neutrons = 15 - 7
= 8
Thus, we can conclude that the given atom contains 8 neutrons in the nucleus.
Each correspond to a principal energy level
Answer:
Boiling point of the solution is 100.78°C
Explanation:
This is about colligative properties.
First of all, we need to calculate molality from the freezing point depression.
ΔT = Kf . m . i
As the solute is nonelectrolyte, i = 1
0°C - (-2.79°C) = 1.86 °C/m . m . 1
2.79°C / 1.86 m/°C = 1.5 m
Now, we go to the boiling point elevation
ΔT = Kb . m . i
Final T° - 100°C = 0.52 °C/m . 1.5m . 1
Final T° = 0.52 °C/m . 1.5m . 1 + 100°C → 100.78°C
