homework for the day.

so yes, today we were assigned to find out on some information based on this question,

What is the relative trend in melting point for the elements in period 3?

Answer :

Melting points generally increase from sodium to silicon, then decrease going down to argon.

so what is the relative trend in boiling point for the elements in period 3?

Answer :

Boiling points generally increase from sodium to aluminium, then decrease to argon.

Here's a table to show the physical data of what i have just said.

Element	Proton number	Symbol	Melting point (K)	Boiling point (K)
sodium	11	Na	371	1156
magnesium	12	Mg	922	1380
aluminium	13	Al	933	2740
silicon	14	Si	1683	2628
phosphorus	15	P	317	553
sulphur	16	S	392	718
chlorine	17	Cl	172	238
argon	18	Ar	84	87

more explanation on the trends,

MELTING

When a substance melts, some of the attractive forces holding the particles together are broken or loosened so that the particles can move freely around each other but are still close together. The stronger these forces are, the more energy is needed to overcome them and the higher the melting temperature.

BOILING

When a substance boils, most of the remaining attractive forces are broken so the particles can move freely and far apart. The stronger the attractive forces are, the more energy is needed to overcome them and the higher the boiling temperature.


So this are all the things that i got from the net about the trends in both melting and boiling point.