Answer: Electronegativity increases as the size of an atom decrease.
Explanation: Electronegativity is the measure of the ability of an atom in a bond to attract electrons to itself.
Electronegativity increases across a period and decreases down a group.
Towards the left of the table, valence shells are less than half full, so these atoms (metals) tend
to lose electrons and have low electronegativity. Towards the right of the table, valence shells are more than half full, so these atoms (nonmetals) tend to gain electrons and have high electronegativity.
Down a group, the number of energy levels (n) increases, and so does the distance between the nucleus and the outermost orbital. The increased distance and the increased shielding weaken the nuclear attraction, and so an atom can’t attract electrons as strongly.
Answer:
Cost to supply enough vanillin is 
Explanation:
Threshold limit of vanillin in air is 
per litre means there should be of vanillin in 1L of air to detect aroma of vanillin.
So, 
So amount of vanillin should be present to detect = 
As cost of 50 g vanillin is 
therefore cost of vanillin = 
the answer is twenty eight
