Answer:- 2.39 mL are required.
Solution:- It's a dilution problem and to solve this type of problems we use the dilution equation:

Where,
and
are molarities of concentrated and diluted solutions and
and
are their respective volumes.
= 1.10M
= 5.00mM = 0.005M (since, mM stands for milli molar and M stands for molar. 1M = 1000mM)
= ?
= 525 mL
Let's plug in the given values in the formula:



So, 2.39 mL of 1.10M are needed to make 525 mL of 5.00mM solution.
We use the gas law named Charle's law for the calculation of the second temperature. The law states that,
V₁T₂ = V₂T₁
Substituting the known values,
(0.456 L)(65 + 273.15) = (3.4 L)(T₁)
T₁ = 45.33 K
an atom that has 18 protons, 18 neutrons and 20 neutrons. This atom has mass number of 38
mass number is calculated as number of protons + number on neutrons
therefore the mass number of the atom = 18+20= 38
Since the atom has a electronic configuration of 2.8.8,the atom cannot be negatively or positively charged because it is stable.
The atomic number of the atom is 18 since atomic number is equal to number of protons
D. 8
You can predict it from it's name "Octet" means Eight. Atom must have that number of electron to have a stable structure!
Hope this helps!