ANSWER
2 valence electrons
STEP-BY-STEP EXPLANATION:
The electronic configuration is given below as

Looking at the configuration, you will see that the last energy carries 2 electrons
Hence, the valence electrons are 2
I think this is learned in chemistry do you have any notes that can help
Answer: Option (c) is the correct answer.
Explanation:
Backbone in a nucleic acids strand is made up of sugar molecules attached with phosphodiester bond.
This sugar-phosphate linkage helps in joining of nucleotides in a DNA sequence. Due to this backbone structural framework of nucleotides is formed. In DNA, the sugar is deoxyribose.
Thus, we can conclude that the backbone in a nucleic acids strand is called sugar backbone.
Answer : The final pressure of the gas will be, 26.8 kPa
Explanation :
According to the Boyle's law, the pressure of the gas is inversely proportional to the volume of the gas at constant temperature of the gas and the number of moles of gas.

or,

or,

where,
= initial pressure of the gas = 209 kPa
= final pressure of the gas = ?
= initial volume of the gas = 10.0 L
= final volume of the gas = 78.0 L
Now put all the given values in this formula, we get the final pressure of the gas.


Therefore, the final pressure of the gas will be, 26.8 kPa
The given compound is being synthesized by condensing
Acetone and
Pivaldehyde (Trimethylacetaldehyde).
First Acetone is treated with
Base, the base abstracts the mildly acidic proton present at alpha position to carbonyl group. The resulting specie called
enolate act as a nucleophile and attacks on highly reactive aldehyde which upon
dehydration yields the
Aldol Product. The Reaction is as follow,