atomic radius

Atomic radius – ½ the distance between nuclei of 2 like atoms in a diameter molecule Increase - as increases of atom size increases the number of shells increases Decrease- more protons and electrons meaning there is more electrostatic attraction

atomic radius

½ the distance between nuclei of 2 like atoms in a diameter molecule Increase -

as increases of atom size increases the number of shells increases

Decrease- more protons and electrons meaning there is more electrostatic attraction

ionisation energy

Ionisation energy – removing of an electron from an atom and forming an ion

Decrease – valence electrons are less attracted to nucleus as they are further from nucleus. Less energy required to remove electron

Increase – valence electrons more strongly attracted to nucleus therefore more energy required to remove an electron

metallic character

Metallic character – describes how closely an element exhibits properties commonly associated with metals

Increase – atoms lose electrons easily due to weaker attraction as electrons are further away from nucleus

Decrease – increase in nuclear charge therefore attraction increases and more difficult to lose valence electrons

electronegativity

Electronegativity – the ability of an atom to attract electrons in covalent bond towards itself ; greater attraction , greater negativity

Decrease - increase in size means less attraction

Increase – increase in nuclear charge and electron, increase of electrostatic attraction

seiving

Sieving – used to separate mixture of solids with different particles size. Particles in the mixture smaller than the mesh passes through a mesh and large particles are left.

filtration

Filtration – used to separate solid particles from liquid/gas

gravitational

Gravitational – uses weight of solid-liquid mixture to push mixture through filter paper

separation funnels

Separation funnels – used to separate liquids with different densities

Denser liquid on top, less dense at bottom. Valve is opened to release allowing bottom layer to separate in different container

evaporation

Evaporation – the process of heating solution until solvent evaporates, leaving solid residue

ditillation

Distillation – separating solution by evaporating, condensing and collecting component of solution with lowest boiling point

fracftional distillation

Fractional – separation of liquids according to their boiling point

quatisation

Electron shells have specific energy levels. Electrons by can move between electron shells by absorbing or emitting specific amounts of energy. The amount of energy have particular frequencies. This corresponds to and is visualised by emission or absorption spectrum

massspect

·       A technique used to measure the mass of atoms/ molecules. In atomic structure this can  be used to identify the presence and relative abundance of isotopic in a sample of an element

Operation

1.      Sample is vapourised and then ionised – sample loses electrons using electron beam to  to becomes positive

2.      Accelerated – ions are sped up through electromagnetic field so they have same kinetic energy

3.      Deflection – ions are separated based on mass-to-charge ratio. Ions deflected by magnetic field, with heavier ion deflected less and amount of deflection depends on number of positive charges – more charge, more deflect

4.      Detection – detector counts ions based on mass to charge ratio

metal bonding

An array of positive ions in a sea of delocalised electrons due to negatively charged electrons being weakly held by positively charged metal nuclei

malleable - metal

·       metal atoms are arranged in layers that can slide over each other when force is applied.

·       This is due to the presence of metallic bonds, where the delocalised electrons are free to move throughout the structure.

·       Electrons can fill the gaps to counteract the repulsive electrostatic force allowing layers of atoms to shift without breaking overall structure.

heat metal

·       Metals conduct heat efficiently because they have free electrons that can move easily throughout the metal.   ·       When heat is applied, these electrons gain kinetic energy and move faster,   ·       This transfers energy quickly from one part of the metal to another, thus conducting heat.

electricity conduct - metal

·       Metals conduct electricity because they have free moving electrons throughout the metal.  

·       Electricity requires charged particles that can move. 

These electrons carry electrical charge, allowing current to flow through the metal when a voltage is applied. 

melting point - metal

·       Metals have a high melting point due to the strong metallic bonds between their atoms. 

·       Each of the negative delocalised electrons are able to non directionally, electrostatically bond to all positive nuclei. 

These bonds require a significant amount of energy to break, resulting in high melting points. 

ionic bonding

metal atoms lose valence electrons during chemical reaction to form positive ions (cations), lost electrons are transferred to non-metal atoms which gain electrons and form negative ions (anions). Ionic substances form 3d crystal lattice held together by strong electrostatic force of attraction between opposite charges.

brittle - ionic

·       Ionic compounds consist of a lattice structure of positive and negative ions.

·       They are brittle because when a force is applied, the ions of like charge can be forced next to each other.  

This causes strong electrostatic repulsive forces between the ions, leading to the material shattering or breaking apart. 

melting point - ionic

·       Ionic compounds have high melting points because they consist of a lattice structure of positive and negative ions  

·       The ions are held together by strong electrostatic forces. 

These forces require a lot of energy to overcome, leading to high melting points. 

solid - conduct - ionic

·       Ionic compounds consist of a lattice structure of positive and negative ions. 

·       Ionic compounds do not conduct electricity in the solid state because their ions are fixed in place within a rigid lattice structure. 

Without free-moving ions, there are no charge carriers to conduct electricity. 

liquid - conduct - ionic

·       Ionic compounds conduct electricity as a liquid because the ions are not held in a fixed lattice and are free to move.  

·       Electricity requires the presence of charged particles that can move. 

When the compound melts, the rigid lattice breaks down, allowing the ions to move and carry electrical charge. 

covalent bond

– modelled by the sharing of pairs of electrons, resulting in electrostatic attraction between the shared electrons and nuclei of adjacent atom

covalent molecular

made up of discrete molecules held together by weak intermolecular bonds

MP - CM

·       Covalent molecular compounds have low melting points because they are held together by weak intermolecular forces, 

 These forces require relatively little energy to overcome, resulting in low melting points. 

conduct - CM

·       Covalent molecular compounds do not conduct electricity in any state because they do not have free-moving charged particles. 

·       Electricity requires the presence of moving charged particles . 

In both solid and liquid states, the molecules are neutral and do not have ions or free electrons to carry electrical charge 

covalent network

composed of extensive network of atoms connected by strong covalent bonds throughout entire 3D lattice structure.

MP - CN

·       Covalent network compounds have high melting points because they consist of a continuous network of covalent bonds.  ·       The covalent bonds are very strong.  ·       These bonds require a significant amount of energy to break, resulting in high melting points.

hard - CN

·       Covalent network compounds have high hardness due to the strong covalent bonds.

·       The atoms are held together in a rigid, three-dimensional structure. 

This makes the material very resistant to deformation. 

conduct - CN

·       Covalent network compounds do not conduct electricity because they lack free-moving charged particles.  

·       Electricity requires the presence of charged particles that can move. 

The electrons are tightly bound in covalent bonds and are not free to move, preventing electrical conductivity 

allotrope

Different structural arrangements of the same type of atom

diamond

strong covalent bonds between carbon atoms in continuous network in 3D lattice.

carbon atoms bond with 4 other carbon atoms forming covalent neetwork lattice

no small molecules - no weak force

not conduct electricity - no moving charged particles

graphite

carbon atoms in layers, within carbon atoms are strong bonds, weak between layers allowing to slide over each other and reduce friction

carbon atoms bond with 3 others

4 valence electron from each carbon atom can move - conduct electricity

fullerenes

Spherical / cylindrical molecules arranged in series of pentagons and hexagons

Conducts electricity but difficult because of curve structure, electrons can’t jump between molecules

nanomaterials

contain particles in the size range 1–100

risk of nanomaterials

small size (~1–100 nm), nanoparticles can enter the human body through inhalation, ingestion, or skin contact. Some nanomaterials penetrate biological barriers, affecting cells and organs.

exothermic

reactions release energy, resulting in products with lower chemical energy than the reactants. Examples include combustion reactions, where energy is released as heat.

endothermic

absorb energy, resulting in products with higher chemical energy than the reactants. The container may feel cold as heat is absorbed from the surroundings.