Bonding Flashcards
What is an ion?
A charged atom or molecule
What is ionic bonding?
The electrostatic attraction between oppositely-charged ions
Who take part in ionic bonding?
Metals and non-metals
What happens to metal atoms when they ionically bond?
They always lose electrons
What happens to non-metal atoms when they ionically bond?
They always gain electrons
What charge do metals ions become when they bond with non-metals?
Positive
What charge do non-metals ions become when they bond with metals?
Negative
What happens when sodium and chlorine react?
An electron is transferred from the sodium to the chlroine, forming two oppositely charged ions, which have strong electrostatic attraction for each other.
Why does Mg2+ O2- have a higher metling point than Na+ Cl-?
Because MgO has a 2+/2- charge which means they have a stronger electrostatic attraction
Why do giant ionic substances have high melting/boiling points?
As all the strong electrostatic attraction between the oppositely-charged ions must be broken down throughout the lattice this requires a huge amount of energy.
When does a covalent bond form?
A covalent bond forms when two non-metal atoms share a pair of electrons
What is a covalent bond?
A covalent bond is the mutual attraction of two nucleii for a shared pair of electrons
table showing how many bonds each group forms in a covalent bond
What is the simpliest covalent bonded molecule?
H2
Why do simple molecular substances have low melting/ boiling points?
- As the covalent bonds between the atoms within molecules are very strong.
- However the forces of attraction bewteen molecules are relatively very weak.
- These intermolecular forces of attraction therefore require little heat energy to overcome them.
What are giant covalent structures?
Giant covalent structures contain many atoms joined together by covalent bonds to form a giant lattice.
Why do giant covalent strctures have high metling/boiling points?
As every strong covalent bond must be brken throughout the lattice this requires a huge amount of energy.
Why do metals conduct electricty?
- Metals conduct electricity bcause their outer-shell elctrons are free to move and so carry charge.
Why and when do ionic compounds conduct electricity?
When their ions become free to move and carry charge, this only happens if they are dissolved (usually in water) or melted.
What i metallic bonding?
It is the electrostatic attraction of positevely-charged ions for the “sea” of their delocalised valence electrons.
Why are metals malleable and ductile?
This is because they consist of layers of atoms. These layers can slide over one another when the metal is bent, hammered or pressed.
What are alloys?
When metals are mixed together to form new metallic substances with new properties.
Why does diamond have a high metling point and is very hard?
As each carbon atom is joined to four other carbon atoms, forming a giant covalent structure.
Why is graphite softer than diamond and why can it carry charge?
- Each layer is held together only by weak intermolecular forces. The layers are therefore easily seperated.
- Each carbon atom in a layer is joined to only three other carbon atoms. So one of the four outer electrons on each atom is not involved in bonding. These electrons are delocalised.
