Bonding and structures Flashcards
What is a covalent bond?
When two or more atoms share pairs of electrons
With which atoms do covalent bonds form?
Two non-metals
What type of bonding forms between two oxygen atoms?
Double covalent bonds
What type of bonding forms between two nitrogen atoms?
Triple covalent bonds
Why do non-metals form covalent bonds?
To complete their outer energy shell
Are covalent bonds strong or weak ?
Very strong
What are the two types of substances that can be made from covalent bonds?
Simple molecular substances and giant covalent structures
What are the characteristics of a simple covalent molecule?
- Only NON-METAL atoms
- Strong bonds IN molecules
- Weak forces BETWEEN molecules
- When broken heated, molecules are not split apart so low boiling point
- Varied Solubility
- Poor Conductor
In simple covalent molecules, what allows them to have a low boiling point?
Weak intermolecular forces of attraction require little energy to be broken
What are most simple molecular molecules at room temperature?
Gases or liquids
Learn these examples of simple covalent molecules
Chlorine
Oxygen
Water
What are the properties of giant covalent structures?
- Only NON-METALS
- High Melting Point
- Insoluble in Water
- Poor Conductor
What is the only exception to the property that giant covalent structures are poor conductors?
Graphite, free electron can carry a charge
Properties of graphite
- 3 Bonds per Carbon
- Free Electrons
- Layers which make it soft and slippery
- Conductor
Diamond
- 4 Bonds per Carbon
- No Free Electrons
- Hard
- Not a Conductor
Main use of graphite
Lubricant, as layers slide over eachother
What do ionic bonds form between?
Metals and non-metals
In ionic bonding electrons are transported where?
From the metal atoms to the non-metal atoms
What do metals become in ionic bonding?
Positively charged ions
What is the electronic configuration of a ion in a ionic bond?
Full outer energy level (like a noble gas)
Where on a ionic bond diagram does the charge and amount of atoms appear?
Top right
Bottom right
What is ionic bonding?
Strong electrostatic attraction between oppositely charge ions
Are ionic compounds soluble?
Yes
What colour are most ionic compounds?
White
What colour are group 1/2 ionic compounds?
Always White
What does the formula of a giant structure show?
Fixed ratio of different elements
Do ionic compounds conduct electricity when molten or in an aqueous solution?
Yes
What are the melting and boiling points of ionic compounds?
Relatively high
Ionic bonding always forms what type of compound?
Giant ionic structure
Giant ionic structure
- High Melting Point
- Soluble in Water
- Conductor
- Lattice structure
How do giant ionic structures form into lattice?
Held together by the attraction between oppositely charged ions
Why do ionic structures have high melting and boiling points?
The electrostatic attraction between oppositely charged ions is very strong, therefore a lot of energy is needed to break them apart
What affects the strength of ionic bonding?
The stronger the charge, stronger forces of attraction occur
E.g 2+ and 2- ions are stronger than 1+ and 1-ions
What are ionic structures made from?
Crystals
Metals
- have high melting points
- are good conductors of heat and electricity
- are hard and dense
- malleable
- ductile
Describe metallic bonding
Positive ions in a lattice, surrounded by a sea of delocalised electrons
What does metallic bonding allow metals to be?
Malleable, ductile, and very conductive
How does metallic bonding enable metals to be conductive?
Delocalised electrons carry charge around the molecule
Why does the metallic structure allow metals to be malleable?
Layers can slide over each other, still stuck together because of “electron sea”
Properties of buckminsterfullerene
“Bucky ball”
- 60 carbon atoms
- arranged in a hollow sphere
What is a fullerene?
Group of allotropes of carbon which are in the form of cages
