Answer:
The strength of an individual H bond depends on the polarity of the H-X bond and therefore on the electronegativity of X ( the more delta positive the H atom, the stronger the electrostatic force of attraction between it and a lone pair of electrons). Thus, on a per bond basis, HF H bonding is strongest. However, as water has two H atoms, each molecule can form two H bonds so on a per molecule basis, water H bonding is strongest (this is evidenced by the boiling points of the three substances; NH3 < HF < H2O.)
Explanation:
Correct me if I'm wrong
Answer:
As you go down group 1, the number of electron shells increases – lithium has two, sodium has three, and so forth. The attraction from the positive nucleus to the negative electron is less. This makes it easier to remove the electron and makes the atom more reactive.
Generally, a liquid freezes exothermally on cooling and a crystal melts endothermally on heating.
The 6 phase changes are vaporization, condensation, freezing, melting, sublimation, and deposition
