Describe General trend in physical appearance of the elements in period 3?

Answer 1

• Sodium, magnesium and aluminum are all good conductors of electricity. Silicon is a semiconductor.
• Sodium, magnesium and aluminum all have metallic structures, which accounts for their electrical conductivity and relatively high melting and boiling points.
• The nuclei of the atoms gets more positively charged.
• Melting and boiling points rise across the three metals
• Silicon has the highest melting point.
• Phosphorus, sulphur, chlorine and argon are simple molecular substances with only van der Waals attractions between the molecules. Their melting or boiling points will be lower than those of the first four members of the period which have giant structures.
• These four substance with simple molecular structures also do not conduct electricity.

Answer 2

The elements in period 3 generally show a trend of increasing atomic number and Atomic Mass from left to right. Additionally, the elements tend to transition from metallic properties on the left to nonmetallic properties on the right. The atomic radii decrease across the period due to increasing nuclear charge and effective nuclear charge.