7.3 Periodicity Flashcards
Why are the boiling points of noble gases so low?
Because they are monatomic gases, and don’t need to be bonded together
What is a metalloid?
An element that is inbetween the diagonal changeover from metals to non-metals
What is the alternate name for a metalloid?
Semi-metal.
What is the state of all metals at room temp? What is the exception?
Solid, except for mercury
Do all metals conduct electricty? Are there exceptions?
All do, no exception
What is metallic bonding?
The strong electrostatic attraction between cations and delocalised electrons.
Describe what has happened to each atom in a solid metal structure.
-Each atom has donated its negative outer-shell electrons to a shared pool of delocalised electrons, throughout the whole structure
-The cations left consist of the nucleus, and the inner electron shells of the metal atoms
What is the name of the structure in a metal?
Giant metallic lattice
How are metal atoms held together?
By bonding in a giant metallic lattice
What are the metallic properties?
-Strong metallic bonds
-High electrical conductivity
-High melting and boiling points
Do metals dissolve in water?
No, they react.
Explain how metals conduct electricity.
The delocalised electrons can move through the metallic structure and carry charge
What does melting point of a metal depend on?
The strength of the metallic bonds holding together the atoms in the giant metallic lattice.
What is the name of the structure that many non-metallic elements exist as?
Simple (covalently bonded) molecules
Describe the structure that simple non-metallic elements exist as.
Simple molecular lattice structure held together by weak intermolecular forces
Describe the arrangement of a giant covalent lattice.
Many billions of atoms held together by a network of strong covalent bonds
Give examples of elements with a giant covalent lattice.
Boron, carbon, silicon
State the properties of a giant covalent.
-High melting and boiling points
-Insoluble in almost all solvents
-Non-conductors of electricity
What is the primary reason for all of the properties of a giant covalent?
The strong covalent bonds that dominate them.
Why are giant covalents insoluble in almost all solvents?
Because the bonds are too strong to be broken by interaction with solvents
Why are giant covalents not conductors of electricity?
Because there are no delocalised electrons to carry charge.
What are the only two giant covalent structures that conduct electricity?
Graphite and graphene
What does the sharp decrease in melting and boiling points from group 14 to 15 mark?
A change from giant to simple molecular structures.
