Periodic Trends (7.3) Flashcards
What’s the trend of the type of element across a period?
The change of metals to metalloids to non-metals.
What is metallic bonding?
The electrostatic attraction between a metal’s cations and delocalised electrons.
What state are all metals, excluding mercury, at room temperature?
Solids.
What’s another covalent structure that isn’t simple?
Giant Covalent structures.
Why are giant structures different to simple covalent?
Giant structures have high melting points and are held together with strong intermolecular forces while simple ones have weak IM forces and low melting/boiling points.
What’s the periodic trend in melting points?
-Melting points increase from group 1 to group 4
-Sharp decrease of melting points from 4 to 5
-Comparatively lower melting points from group 5 onwards.
What are simple covalent structures held together by?
Weak London/Induced dipole-dipole interactions
Why is there a sharp decrease from group 4 to group 5?
Transition from giant to simple structures.
Why can’t most giant covalent structures conduct electricity?
They have no delocalised electrons or ions.
Why can metal structures conduct electricity?
Delocalised electrons.
Why do covalent structures have high melting points?
Strong covalent bonds need a lot of energy to be overcame.
Why do metals have a high melting point?
The electrostatic attraction between cations and delocalised electrons need a lot of energy to be overcame.
Why can graphene and graphite conduct?
They have delocalised electrons.
Do metals and covalent structures usually dissolve?
No.
