C2.2 Bonding Flashcards
Metals vs non metals characteristics
Metals | non metals
Shiny | dull
High melt and boil point | low melt and boil point
Malleable | brittle
Ductile | not ductile
Heat and electricity good conductors | heat and electricity bad conductors
Old group numbers of periodic table and IUPAC group numbers
Old group numbers from 1 to 0
IUPAC group numbers from 1 to 18
What is periodic table
Table which all the elements are arranged in rows and columns.
In order of increasing atomic number (modern periodic table).
Metals on left
Non metals on right.
Chemical properties of metals and non metals
Metals lose electrons to form + ions
Non metals gain electrons to form - ions
Metals DON’T react with each other
Non metals react with each other to produce compounds that consist of molecules.
Both may react with oxygen producing oxides
Metal oxides dissolved in water make alkaline solution and non metal oxides produce acidic solutions.
Periods and groups on the periodic table
Periods - horizontal - rows - Where each atom has the same number of occupied electron shells
Groups - Vertical - columns - elements have similar properties due to the arrangement of their electrons.
How many electrons per outer shell
Electronic structure of an element
Shows how the electrons are arranged in its atoms.
Outer shell
Outermost occupied electron shell.
Arrangements of electrons around the nucleus
Around the nucleus in shells - different shells can hold different numbers of electrons
Shell - maximum number of electrons
First - 2
Second - 8
Third - 8
Fourth - 18
Work out electronic structure
Counting from hydrogen, period by period until you reach the element you want.
Period 1: 2 electrons in outer shell
Period 2: 8 electrons in outer shell
Period 3: 6 electrons in outer shell
Ion
Electrically charged particle formed when an atom, group of atoms loses or gains electrons.
Atom with equal numbers of protons and neutrons but has different number of electrons. The overall charge can be positive or negative (charged particles)
Metals form + ions as they lose electrons
Non metals gain electrons and form - ions.
When drawing an electron diagram
Ions go inside brackets
Element symbol written in the centre
Dots in element 1 crosses in element 2 to represent the electrons
What happens when a metal reacts with a non metal
Electrons are transferred from the metal’s atoms to the non metal’s atoms.
Structure and bonding in ionic compounds
Contain positive and negative ions arranged in a regular way.
This arrangement is giant ionic lattice
Giant = arrangement repeated many times
Ionic = Held in place with ionic bonds, that act in all directions
Are strong electrostatic forced of attraction
Lattice = arrangement is regular and not random.
Happens between a metal and non metal
formed when one or more outer shell electrons are transferred from metal atom to non - metal atom
What is a covalent bond
Shared pair of electrons to complete each atom’s outer shell
Happens between 2 non metals
involve electrostatic forces of attraction between the nucleus of each bonded atom and the shared electrons
Strong bonds
What is a molecule
Particle in which non metal atoms are joined to each other with covalent bonds
Ball and stick model
Limitations:
sizes of atoms and ions are inaccurate
Shows that atoms or ions held by forces and not physical bonds
atoms or ions too far apart
Ion charges not shown
Displayed formula
Each atom is represented by its chemical symbol
Each covalent bond is a straight line
Limitations:
Does not show the 3D shape of the molecule.
What is a giant covalent structure
Consists of many non-metal atoms joined by covalent bonds and arranged in a repeating regular pattern
Have many atoms
What are all polymers made from
Monomers
Join end to end in chemical reactions
What are monomers
Simple molecules
Few non metal atoms joined by covalent bonds
Thermosetting polymer
Chains Joined together by strong covalent bonds - cross linking
Thermosoftening polymers
The polymer chains in the tangled web are easy to separate when energy is given to them.
Structure of metals
Solid state at room temperature except from mercury
Atoms packed together in a regular way forming a giant metallic lattice.
Modelled by drawing circles or spheres arranged in a regular pattern, touching each other.
Metallic bonding
Metals lose electrons to form positive ions.
Electrons leave the outer shells of the metal atoms, forming a “sea” of electrons around positively charged metal ions.
These are free to move through the structure of the metal, so they are called delocalised electrons.
The electrons from the outer shells of the metal atoms are delocalised, are free to move through the whole structure. This sharing of delocalised electrons results in strong metallic bonding.
Strong electrostatic forces of attraction between the delocalised electrons and the closely packed positive metal ions.
What did Mendeleev do
Arranged all the elements in order of increasing atomic weight
Grouped together the ones with similar chemical properties
Left spaces for elements he thought would exist but not yet found
In 1871 he rotated his table so that the groups were in columns.
What did Moseley find out
Atom’s atomic number was actually the number of protons in the nucleus
Group 1 of the periodic table
Group: 1
Type of element: metals
Reactivity: very reactive
Electronic structure: end in 1
Ions formed in reactions: +1
Group 2 of the periodic table
Group: 2
Type of element: metal
Reactivity: reactive
Electronic structure: end in 2
Ions formed in reactions: +2
Group 7 of the periodic table
Type of element: non metal
Reactivity: very reactive
Electronic structure: end in 7
Ions formed in reactions: -1
Group 0 of the periodic table
Group: 0
Type of element: non-metal
Reactivity: very unreactive
Electronic structure: outer shells are full
Ions formed in reactions: do not react/inert
Do atoms have neutral overall charge
Yes
same number of negatively charged electrons as positively charged protons.
When do ionic compounds conduct electricity
When molten or aqueous (dissolved in water)
name of compounds made only from carbon atoms and hydrogen atoms
Hydrocarbons
