Answer:
As you move from left to right, the nucleus gains protons. This increases the positive charge of the nucleus and its attractive force on the electrons. At the same time, electrons are added to the atoms as you move from left to right across a period.
Explanation:
Ca +2
At -1
In +3
Sr +2
Ra +2
Fr +1
Ba +2
As -3
Hydrogen Bonding will effect the boiling point the most. Let's take an example Butane a four carbon unsaturated organic compound with molecular formula C₄H₁₀ and boiling point -1 °C.
H₃C-CH₂-CH₂-CH₃
Now, replace one hydrogen on terminal carbon with -OH group and convert it into Butanol.
H₃C-CH₂-CH₂-CH₂-OH
The Boiling point of Butanol is 117.7 °C. This increase in boiling point is due to formation of hydrogen bondings between the molecules of Butanol.