Period 3 Melting/Boiling Points in Period 3

ElementDescription Na They are metals. They have giant structures. They lose their outer electrons to form ionic/metallic structures. Mg Al SiFour electrons in its outer shell, it forms four covalent bonds (like carbon- diamond). PThey are non-metals. They either accept electrons to form ionic compounds or share electrons to form covalent compounds. S Cl ArHas a full outer shell (3s,3p) and is unreactive. Melting/Boiling Points in Period 3 Period 3

Melting/Boiling Points in Period 3 Melting/boiling points are determined by both bonding and structure. Therefore there are huge changes in bpt/mpt.

Melting/Boiling Points in Period 3 Bonding:  metallic   covalent  M. Pt./ O C: Element: Na Mg Al Si P 4 S 8 Cl 2 Ar Structure:  giant lattice   molecular  atomic Increase? highest mpt? variation?

Melting/Boiling Points in Period 3 Increase in melting point from Na to Al The charge on the metal ion increasing +1 to +3 Increasing number of delocalised electrons The size of ions decreases Increasing nuclear charge Therefore the strength of metallic bonding increases M. Pt./ O C: Element: Na Mg Al Si P 4 S 8 Cl 2 Ar

Melting/Boiling Points in Period 3 Si has the highest melting point Giant covalent structure, similar to diamond’s. Strong covalent bonds in three dimensions. M. Pt./ O C: Element: Na Mg Al Si P 4 S 8 Cl 2 Ar

Variation from P 4 to Ar Melting points determined by van der Waal forces The melting points reflect the number of electrons in the molecules P 4 = 60, S 8 = 128, Cl 2 = 34 M. Pt./ O C: Element: Na Mg Al Si P 4 S 8 Cl 2 Ar variation? Melting/Boiling Points in Period 3