C2.2 Flashcards
What type of ions do metals form
Metals lose electrons to form positive ions
What type of ions do non-metals form
Metals gain electrons to form negative ions
What PH solution do metals and non metals form when their oxides are dissolved in water
Non metals - acidic solutions
Metals - alkaline solutions
Physical properties of metals
Shiny, high melting and boiling point, solid, malleable, ductile (can be pulled into wires) and are good conductors
Physical properties of non metals
Dull, low melting and boiling points, 1/2 solid and 1/2 gas, brittle, no-ductile, insulators
What is a horizontal row in the periodic table called
A period
What is a vertical column in the periodic table
A group
What does the group number mean
It is the number of electrons that are in the outer shell.
What does the period number mean
The number of electron shells that the element has
An atom will always follow the easiest path to become an ion
For example sodium loses an electron
What happens when a metal reacts with a non metal
When a metal reacts with a non metal electrons are transferred from the metal to the non-metal so both achieve a more stable electronic structure.
What can you model an ionic compound with
A dot and cross diagram, where the dots and crosses represent electrons.
What must you do to the charges
Balance the charges so that they are equal
Properties of an ionic structure
High melting point as there are lots of strong ionic bonds
Brittle as the layers slide over each other when a force is applied -> some charges come close together -> electrostatic repulsion -> shattering
Not conductive in a solid.
Conductive in liquid as positive ions and negative ions are free to move so can complete a circuit.
Soluble in polar solvents.
What is the bond in an ionic compound
The bond in an ionic compound is between the positively charged metal ion and the negatively charged non metal ion
What is a covalent bond
A covalent bond is a shared pair of electrons between two non metal atoms. By sharing electrons they complete their outer shells.
what is a simple molecule
A molecule that only contains a few atoms. They can be modelled using a dot and cross diagram
What is the electrostatic force of attraction in a covalent bond
they are between the positively charged nucleus of the atoms and the shared electrons
Why do simple molecules have a low boiling and melting point
They have a low boiling and melting point as the intermolecular forces between molecules are weak.
What is a giant covalent substance
A giant covalent substance consists of lots of non-metal atoms covalently bonded and in a repeating pattern called a giant lattice/giant covalent lattice.
What is the chemical formula for giant covalent structures written as
The chemical formula is written empirically
Diamond
Properties -
hard as it has many strong covalent bonds a high melting point and a high boiling point
Unreactive
transmits light
Bonding - each carbon atoms is bonded to 4 other carbon atoms (each atom is stable and un reactive)
No intermolecular forces only covalent bonds
Graphite
Properties:
brittle
soft
conducts electricity as there are delocalised electrons
good conductor of heat
lubricant as layers of graphite can slide over each other
Bonding:
Weak intermolecular forces between layers
Each carbon atom bonded to 3 carbons
Each carbon has one double bond an a single bond
Silicon dioxide
Properties:
Transparent
Brittle
Bonding:
Each silicon atom is bonded to 4 oxygens and each oxygen to 2 silicons
Formula SiO2
What are polymers made from
Polymers are made from many smaller molecules called monomers. They are able to join end to end in chemical reactions producing longer polymer molecules.
What are monomers
Monomers are simple molecules consisting of a few non-metals joined together by covalent bonds
Properties of polymers
Can’t conduct electricity
Lots of covalent bonds
Longer polymers have high melting/boiling pints as the longer they get the stronger intermolecular forces are
A property of metals (melting and boiling points)
All metals (apart from mercury) are solid at room temperature. Their atoms are packed together in a regular way forming a giant metallic lattice.
Structure of metals
Positive metallic ions surrounded by a sea of delocalised electrons
What is the electrostatic forces of attraction in a metal
Strong electrostatic forces of attraction between the delocalised electrons and positively charged metal ions
Properties of metaks
Malleable - as the layers of metal ions can slide over each other and the sea of delocalised electrons is free to move meaning that when the do bonds aren’t broken
Conducts electricity - it has free to move delocalised electrons
High melting point - lots of strong metallic bonds
Ductile
How did Mendeleev organise the periodic table
Mendeleev organised the elements by increasing atomic mass.
If an element shared properties with a group of elements it was rearranged so they were together
He left gaps where no known elements fitted with the chemical properties of the group.
what does group 8 consist of
Unreactive gases
What is the pattern of chemical properties in the periodic table
Elements arranged in order of increasing atomic number
Electronic structure is determined by the number of electrons
Electronic structure determines its chemical structure
