1 Structure and bonding Flashcards
What is the charge of the ions in each group?
- +1
- +2
- +3
- left out
- -3
- -2
- -1
- left out
Why do groups 4 and 0 not follow the pattern of charges of ions?
Group 0 already has a full outer electronic shell so will not need to form an ion which has lost or gained electrons
Group 4 only has 4 electrons on its outer shell but its half stable so it won’t take or give electrons to become a charged ion
Why do ionic compounds have high melting and boiling points?
Because they form a lattice with opposite charged ions attracting each other very strongly which means it requires more energy to break apart the bonds
What are the conditions of the charge for ionic compounds?
They must balance out to be a neutral charge- 0
They cancel each other out
What is ionic bonding a bond between?
A metal and a non metal
What is a compound?
A substance containing 2 or more elements which are chemically combined
How do atoms achieve a stable arrangement in covalent bonding?
By sharing electrons
How do atoms achieve a stable arrangement in ionic bonding?
By transferring electrons
What is the very strong force of attraction called in ionic bonding?
The electrostatic force of attraction
What do we call the structure of an arrangement of ions in ionic bonding?
A giant structure (lattice)
What does the formula of an ionic compound show?
The ratio of ion present in the compound
How are the atoms in molecules held together in covalent bonding?
By shared pairs of electrons which are called strong bonds between the atom’s covalent bonds
Name two examples of giant covalent structures…
Diamond: each carbon atom forms four covalent bonds with its neighbours forming a rigid lattice
Silica/ silican dioxide
What are the general properties of giant covalent structures?
- the bonds are very strong
- the bonds have a regular geometry
- the atoms form a very strong lattice
Nitrogen and carbon dioxide are very nonreactive… what does this tell us about covalent bonds?
The bonds are strong and stable
Intramolecular bonds
Not interested in other reactions
Why are most covalent bonded compounds gases?
The intramolecular bonds are strong and stable
What are the structures of metals like?
Metals have giant structures made up of metal atoms which are closely packed together and arranged in regular patterns of layers
This means they can form crystals
When are you likely to be able to see crystals on the surface of metals?
- surface of aluminium foil
- on iron objects which are galvanised to protect from rusting (zinc coated)
How does metallic bonding work?
- Metal ions are held together by electrons from the outermost shell (highest energy level) of the metal atoms
- The positive ions that this produces (and the sea of ‘free’ electrons) are held together by strong electrostatic forces which bond the metal ions like glue
- The electrons in metals are free to move around throughout the structure
What are the outermost electrons in a metal atom termed as and what do they do?
They are described as a sea of DELOCALISED electrons which rapidly move binding the ions together
True or false? ‘The more electrons there are in its outer shell, the stronger the metal structure’
True
How do metals conduct electricity?
The free delocalised electrons are able to attract to the ions so they can conduct the electricity and transfer the charge to other ions quickly
How do metals conduct heat?
Free, delocalised electrons absorb electricity and gain energy, turning into kinetic energy as they move and vibrate- this means they hit each other and more energy is passed between them, generating heat
Why do metals have high melting and boiling points?
The bonds have to break to metallically bond, therefore a lot of energy is used to do this- this means that there are high melting and boiling points because of the energy needed to turn it into a liquid/gas- their electrons are strong
