Bonding Structure Flashcards
What is ionic bonding?
When particles are oppositely charged ions
What is covalent bonding?
When particles are atoms which share pairs of electrons
What is metallic bonding?
When particles are atoms which share delocalised electrons
What are ions?
Charged particles
Why do atoms lose or gain electrons?
To get a full outer shell
Why do atoms want a full outer shell?
To have a stable electronic structure
How do metals form ions?
By losing electrons
What do metals form when they lose electrons?
A positive ion
How do non-metals form ions?
By gaining electrons
What do non-metals form when they gain electrons?
A negative ion
What are cations?
Positive ions
What are anions?
Negative ions
What is ionic bonding with?
A metal and non-metal
How are oppositely charged ions attracted to each other?
By electrostatic forces
What structure do ionic compounds have?
Regular giant lattice structure
What is a regular giant lattice structure?
Ions closely packed in a regular lattice arrangement with strong electrostatic forces of attraction between oppositely charged ions, in all directions in the lattice
What are properties of ionic compounds?
High melting + boiling point Can't conduct electricity when solid Can carry current when molten or dissolved Soluble Brittle
Why do ionic compounds have a high melting and boiling points?
Because there are many strong bonds between ions and a lot of energy is needed to overcome this attraction
Why can’t ionic compounds conduct electricity when solid?
Ions are held in place
Why can ionic compounds conduct electricity when molten or dissolved?
Ions are free to move
Why are ionic compounds brittle?
When a force is applied, the pattern is disrupted so like ions are forced together. Like charges repel and the repulsion breaks the lattice structure
What happens to the ions when dissolved?
They separate and are free to move in the solution
What is covalent bonding with?
Non-metals
What do non-metals do to make covalent bonds?
Share pairs of electrons
Why are covalent bonds strong?
The positively charges nuclei of the bonded atoms are attracted to the shared pair of electrons by electrostatic forces
Which electrons do atoms share?
Electrons in their outer shells (highest energy level)
What are simple molecular substance made up of?
Molecules containing a few atoms joined together by covalent bonds
Are the forces of attraction between simple molecular substances strong or weak?
Weak
Why are melting and boiling points of simple molecular substances low?
The molecules are easily parted from each other because of weak intermolecular forces
What happens as molecules get bigger?
The strength of the intermolecular forces increases, so more energy is needed to break them. This means that the melting and boiling point increases
Why don’t molecular compounds conduct electricity?
Because they aren’t charged - have no free electrons or ions
What are polymers?
Lots of small units linked together to form long molecules that has repeating section
How are atoms in a polymer joined together?
By covalent bonds
What is the difference between intermolecular forces between polymer molecules and simple covalent molecules? What does this mean?
The intermolecular forces between polymer molecules are bigger, so more energy is needed to break them - higher melting and boiling points
Are the intermolecular forces between polymer molecules stronger or weaker than ionic or covalent bonds?
Weaker , so lower boiling points than ionic or giant molecular compounds
How are atoms in giant covalent structures bonded?
All the atoms are bonded to each other by strong covalent bonds
Why do giant covalent structures have high melting and boiling points?
Because lots of energy is needed to break the strong covalent bonds between the atoms
Why don’t giant covalent structures conduct electricity?
Because they don’t contain charged particles
How many covalent bonds does each carbon atom form in diamonds?
4
Why are diamonds hard?
They have a very rigid giant covalent structure