2.1 - Structure And Bonding Flashcards
What is a compound?
Two or more elements chemically combined
What is a chemical bond?
An attraction between particles
What do substances that have that consist of simple molecules?
Low melting and boiling points
Weak intermolecular forces
What is ionic bonding?
When a non-metal and a metal combine by transfer of electrons
What happens when the metal element loses electron(s) in ionic bonding?
It produces a full outer shell and becomes a positive ion - this is because it has lost electron(s) meaning it has more protons which are positive
What happens when the non-metal gains electron(s) in ionic bonding?
It produces a full outer shell and becomes a negative ion - this is because it has gained electron(s) meaning it will have more electrons which are negative
Why do the ions bond in ionic bonding?
Negatively charged ions are attracted to positively charged ions as oppositely charged ions attract
What is the attraction between the ions in ionic bonding?
They have a strong electrostatic attraction between positive and negative ions
What is the melting point of an ionic bond?
High melting point
Can ionic bonds conduct electricity?
They conduct when dissolved in water or molten as the bond between the ions are broken and are free to move
What is covalent bonding?
When a non-metal and another non-metal combine by sharing electrons
What are substances made from covalent bonds called?
Molecules
What are the force like in simple covalent bonding?
They have weak intermolecular forces but strong bonds between atoms where electrons are shared
What is the melting and boiling points in simple covalent bonding?
Low melting and boiling points
Do simple covalent bonds conduct electricity?
They can’t conduct as they have no charge
Which 3 Giant covalent structures do you need to know about?
Diamond, Silicon Dioxide and Graphite
What is the structure of a normal giant covalent bond?
Repeating 3D structure
Each carbon has 4 bonds (diamond)
Strong bonds between atoms
Hard materials
What is the melting and boiling points in giant covalent bonding?
High Melting and Boiling Points
Do normal giant covalent structures conduct electricity?
They don’t conduct electricity as they have no free atoms therefore no delocalised electrons. It is also insoluble in water
What is the structure of Graphite?
Hexagonal rings of carbon 1 atom thick in layers
Each carbon has three bonds
Can Graphite conduct electricity?
Yes as each carbon only has three bonds meaning it has one free electron per carbon atom not involved in bonding. This electron is delocalised and free to move allowing graphite to conduct electricity
What are the forces between the layers in Graphite?
It has weak intermolecular forces so the layers can slide over each other - component in lubricants
What are fullerenes?
A form of carbon (allotropes) made up of balls cages or tubes
What can fullerenes be used for?
Drug delivery
Lubricants
Catalysts
In nanotubes e.g tennis racket
Properties of a fullerene?
Strong but light
Large surface area
What is metallic bonding?
When a metal and another metal element are combined
How are metals bonded?
The outer electrons in the metal lattice become delocalised leaving a lattice of positively charged electrons
The electrostatic attraction between the positively charged metal ions and the negatively charged sea of delocalised electrons creates a strong metal bond
What is the melting and boiling points in metallic bonding?
Hight melting and boiling points
Can metallic structures conduct electricity?
Yes as delocalised electrons carry the electrical charge
Properties of metals?
Malleable and ductile as layers cans slide over each other
Shiny and sonorous (ding!)
What are alloys?
Made from two or more metals with different sizes distorting the atom layers
What properties of alloys make them better than metals?
They can’t slide over each other making them much harder
What is a shape memory alloy?
They can return to their original shape when heated after being deformed
Give an example of a shape memory alloy?
Nitinol
Made from Nickel and Titanium
