periodicity

Question 1

what is the structure of silicon

Answer 1

giant covalent structure

Question 2

what is the structure of carbon

Answer 2

giant covalent

Question 3

The melting points of elements in Period 3 vary across the period. Describe and explain this trend.

Answer 3

Na, Mg, and Al have metallic bonding.

Metallic bonding strength increases from Na → Al:

More protons (higher nuclear charge),

Smaller atomic radius,

More delocalised electrons.
→ So stronger attraction between ions and electrons → melting point increases.

Si has a giant covalent (macromolecular) structure → very strong covalent bonds → very high melting point.

P₄, S₈, and Cl₂ are simple molecular → weak van der Waals forces between molecules.

Melting points decrease sharply from Si → P → S → Cl due to decreasing strength of van der Waals (S₈ has highest of these due to more electrons/larger molecule).

Question 4

what factors effect ionisation energy

Answer 4

sheilding, atomic radius and neuclear charge

Question 5

what is the trend in ionisation energy accorss a period

Answer 5

increases

Question 5

what is the trend down a group for ionisation energy and why

Answer 5

decreases as atomic radius and sheilding effects increase

Question 6

explain the trend in atomic radius accross a period

Answer 6

neuclear charge increases so outer shell electrons are attracted and drawn in more stongly to the neucleus