1.2 b Bonding relating to properties Flashcards
Why do elements take part in reactions?
To achieve a full outer shell
To achieve a stable electron arrangement
To achieve a noble gas electron arrangement
What is a covalent bond?
A shared pair of electrons
What type of elements form covalent bonds?
( LO : 18 )
Noin - metal elements
What holds the atoms together when they form covalent bonds?
( LO : 17 )
The common (electrostatic) attraction the nuclei have for the shared pair of electrons.
How do non-metal atoms achieve a full outer shell when they react with one another?
They share unpaired electrons
Why do elements take part in reactions?
( L.O.19)
To achieve a full outer shell and achieve a noble gas electron arrangement.
How do non-metal atoms achieve a full outer shell when they react with one another?
( L.O.19)
They share unpaired electrons
What are the 7 elements that exist as diatomic molecules?
( L.O. 20)
What is meant by a diatomic molecule?
( L.O. 20)
A molecule made up of 2 atoms
What 4 shapes of molecules must we know?
( L.O 21)
What are the properties of covalent molecular substances?
( L.O. 24)
Why do covalent molecular substances have low melting and boiling points?
( L.O. 24)
Why do covalent network substances have high melting and boiling points?
What are the properties of covalent network substances?
What is a molecule?
Are covalent molecular substances soluble in any other liquids?
Yes. Hexane for example
What is an ion?
An atom which has lost or gained electron(s)
What kind of elements take part in ionic bonding?
Metals reacting with non-metals
Why do metals lose electrons to form positive ions?
To obtain a full outer shell
How many electrons do metals lose to form ions?
The number of valence electrons that they have.
e.g Na loses 1
Mg loses 2
What charge do metal ions have when they lose electrons?
They take on the corresponding positive charge as the number of electrons they lose.
e.g Mg loses 2 electrons to become Mg2+
Why do non-metals form negative ions?
They gain electrons (-1 charge) to complete their outer shell.
Why is water a “polar” molecule?
Why are many ionic compounds soluble in water?
Why do ionic substances conduct in solution but not in solid state?
The ions are free to move in solution but are trapped in the lattice in the solid
Why do ionic compunds have high melting points?
Do ionic substances conduct in
- Solid state
- Solution
- Liquid state
- No
- Yes
- Yes
Recognising an ionic lattice
( LO 32)
What is meant by a lattice?
A regular, repeating, 3-D structure.
What is electrolysis?
The breaking apart of an ionic substance using electricity
What type of current is used in electrolysis and why?
DC current
To ensure separate products form at each electrode
What happens at the negative electrode during electrolysis?
Reduction of metal ions into metal atoms.
Reduction is gain of electrons
What happens at the positive electrode during electrolysis?
Oxidation
Negative ions lose electrons to form atoms (usually as molecules)
Do ionic compounds have low or high melting points?
(LO 33)
High
Why are many ionic compounds soluble in water?
( LO 34 )
Polar water molecules are able to attract the ions and break the lattice
What is the conductivity of ionic substances?
( LO 35)
