Answer:
1 atm
Explanation:
The normal boiling point of a liquid is temperature at which the vapour pressure of the liquid equals 1 atm.
If the normal boiling point of cyclohexane is 81.0 °C, the vapour pressure of the liquid is 1 atm.
The graph below shows that the vapour pressure of cyclohexane reaches 1 atm at about 81 °C.
Answer: alkaline earth metals (group-IIA)
Explanation:
The element which donates the electron is known as electropositive element and forms a positively charged ion called as cation. The element which accepts the electrons is known as electronegative element and forms a negatively charged ion called as anion.
Alkaline earth metals donate 2 valence electrons to acquire noble gas configuration.
For example: Berrylium is the first alkaline earth metal with atomic number of 4 and thus has 4 electrons
Electronic configuration of berrylium:
Berrylium atom will loose two electrons to gain noble gas configuration and form berrylium cation with +2 charge.
Thus Elements donate 2 electron to produce a cation with a 2+ charge are alkaline earth metals.