Paper 1: Structure and bonding Flashcards
What is Ionic bonding?
Electrostatic attraction between positive and negative ions
How are Ionic bonds held together?
In a giant lattice, held together by electrostatic attraction between positive and negative ions
Properties of ionic substances
High melting and boiling points
Do not conduct electricity when solid
Conduct when molten or dissolved in water
How are ionic compounds formed?
Reaction of a metal and a non-metal
Metal loses an electron and transfers it to non-metal which gainsit
What is a covalent bond?
Shared pair of electrons between two atoms
Describe structure and properties of SIMPLE molecular substances
-Do not conduct electricity
-Weak intermolecular forces so low melting and boiling point
-small molecules
How do intermolecular forces change as mass/size of molecule increases
Increase causing melting and boiling points to also increase
What are giant covalent substances?
-Solid atoms covalently bonded in a giant lattice
-high melting/ boiling points
-Most dont conduct electricity
Properties of diamond
-high melting/boiling point
-hard
-For covalent bonds per carbon atom
-does not conduct electricity
Properties of graphite
-Layers of hexagonal rings
-3 covalent bonds per carbon atom
-High melting point
-Weak intermolecular forces
-Conduct thermal/ electricty
Properties of fullerenes
-Hollow shaped molecules
-Hexagonal rings
What is metallic bonding?
Forces of attraction between delocalised electrons and positive ions
Properties of metals
-High melting/boiling points
-Good conducters of heat/elecricity
- Malleable
Alloys
Mixture of a metal with another element, usally a metal
Why are alloys harder than metals
Different sizes of atoms distorts the layer so they cant slide over each other
