topic 2 bonding Flashcards
What are ions
Ions are charged particles that have single atoms or groups of atoms
How are ions formed
By gaining or losing electrons to form a complete outer shell
Gain= Non metal (anions) Group 1 and 2
Lose= Metal (cations) Group 6 and 7
How can you identify elements charge
Group number same number of outershells
What is ionic bonding
Is when a metal and non-metal react together
What happens to a metal and non metal atom in ionic bonding
Metal loses becomes positively charged
Non metal gains becomes negatively charged
What structure do ionic compounds form
Giant ionic lattice
Why do ionic compounds have high melting and boiling points
As they have strong electrostatic forces between oppositely charged ions which requires a lot of energy to break
Can ionic compounds conduct electricity
Yes only when they melt as ions can freely move around and carry electrical charge
What is covalent bonding
The sharing of electrons between two non metals
What holds atoms together in an electrostatic bond
The electrostatic attraction between shared electrons and the nuclei of bonded atoms
What are simple molecular substances
Covalently bonded molecules with weak intermolecular forces
What are the properties of simple molecular substances
Low melting & Boiling points
Don’t conduct electricity
Weak intermolecular forces
Why do simple covalent molecules have low melting and boiling points
As they have week intermolecular forces
Why don’t simple covalent molecules conduct electricity
As they don’t have free electrons or charged particles
Give examples of simple covalent molecules
Water (H2O)
Carbon dioxide (CO2)
Methane (CH4)
What are giant covalent structures?
A substances where all atoms are joined by covalent bonds in a large network.
What are the key properties of giant covalent structures?
High melting and boiling points
Do not conduct electricity (except graphite)
Strong covalent bonds
What are the properties of diamond?
Hardest known natural material
High melting and boiling points
Does not conduct electricity
Each carbon forms 4 covalent bonds
What are the properties of graphite?
Soft and slippery (layers can slide)
Conducts electricity (delocalised electrons)
High melting and boiling points
Each carbon forms 3 covalent bonds
What are the properties of silicon dioxide?
Hard
High melting and boiling point
Doesn’t conduct electricity
What is metallic bonding?
The attraction between positive metal ions and a sea of delocalised electrons.
What are the properties of metals?
High melting and boiling points
Conduct electricity and heat
Malleable and ductile
Why are metals good conductors of electricity?
Delocalised electrons move freely, carrying charge.
Why are metals malleable?
Layers of atoms can slide over each other without breaking the metallic bond.
