Answer:
The answer to your question is: B and C.
Explanation:
Neon atomic number = 10
Electron configuration is not : 1s²2s¹2p⁶ .
This electron configuration is for fluor (9 electrons) because is we sum up the electrons ( 2 + 1 + 6) the result is 9.
A)The 3s orbital should be part of the configuration. This is not the right reason.
B)The total number of electrons is incorrect. This correct, the number of electrons is 9 instead of 10.
C)The 2s orbital does not have enough electrons. This option is correct, 2s must have 2 electrons and it only has 1.
D) The 1s orbital does not have enough electrons. This option is incorrect, 1s orbital can have only 2 electrons.
Answer : The volume for 6.0m HCl solution required = 62.5 ml
Solution : Given,
Initial concentration of HCl solution = 6.0m
Final concentration of HCl solution = 1.5m
Final volume of HCl solution = 250 ml
Initial volume of HCl solution = ?
Formula used for dilution is,

where,
= initial concentration
= final concentration
= initial volume
= final volume
Now put all the given values in above formula, we get the initial volume of HCl solution.

= 62.5 ml
Therefore, the volume for 6.0m HCl solution required = 62.5 ml
To measure weight of a item