1, 2, 3 for test 1 Flashcards
Molar mass measured in vs atom
g/mol is molar mass as you can measure it yourself. A singular atom is measured in amu as it is very small
Bohr’s model
Full electron diagram for atom showing protons, neutrons and electrons and energy shells
Cations
Metal ions, want to loose electrons. Have a low first ionisation energy, loose electrons to become positive.
First Ionisation energy
energy required to remove the outer most electron from an atom.
Group on the periodic table - dictate
Vertical columns that indicate how many electrons are in the valance shell of atoms.
Period number of an element
Rows on the periodic table. Tells us how many electron shells atoms have.
Atomic radius
Distance between the nucleus and the valance shell.
Electronegativity
Ability of an atom to attract electrons.
Down a group atomic radius
- atomic radius increases as more electron shells
Electrostatic attraction
Force of attraction between electrically charged particles due to their opposite charges
Across a period atomic radius
- Atomic radius decreases as more proteins means stronger charge of nucleus that pulls electrons in tighter
Across a period 1st IE
- 1st IE increases as it is harder to loose e as the nuclear charge is acting over a shorter distance so energy required to remove an e increases
Across a period electronegativity
- increases excluding group 18 as the nuclear charge increases as more protons in nucleus so increased attraction to electrons
Down a group 1st IE
- 1st IE decreases as decrease in electrostatic attraction
Down a group electronegativity
- decreases as the atomic radius increases so decrease in electrostatic attraction so less attraction to electrons
Reactivity - position on period table
Elements that are more reactive gain/loose electrons more easily to have a stable electron configuration. Non metals in group 17 and metals in group 1 and 2.
Properties of elements in the same group
Same number valence e, same charged ions, same bonding capability
Properties of elements in the same period
Same number of electron shells
Isotopes definition
Atoms of the same element (same number of protons) but differing numbers of neutrons. C-12, C-13, C-14
Isotope properties
Same chemical properties (reactivity and charge of ions) but different physical properties (density, mass and melting point)
Same chemical properties
same chemical properties react similarly in chemical reactions. Atoms in the same group have same chemical properties.
Same physical properties
same physical properties exhibit similar characteristics related to their physical state or appearance or mpt/bpt
Mass spec
Separates isotopes based on their mass. It is a technique that identifies which isotopes are present as well as their abundance. Determines the relative atomic mass of elements.
Relative atomic mass measures in
measured in amu. Atomic mass units.
Calculate relative atomic mass - equation
RAM = %1 x M1 + %2 x M2
etc
Stoich ratio equation
N unknown = u/k x nknown
Percentage by mass calculation (carbon)
%c = mass C/mass CO2 x 100
Transition metals
Have to specify their charge
ide
Non metal element as an ion
ate
Polyatomic ion with maximum amount of oxygens it can handle
ite
element with 1 less oxygen than ates
Conductivity
Ability to conduct electricity, allowing the flow of an electric current, mobility of charge carriers (electrons or ions)
Ionic bonds
electron distribution, physical properties and conductive properties
- Cations loose e and Anions gain, form a lattice structure of pos and neg charged ions
- Very high mpt/bpt, crystal lattice structure is brittle
- Not conductive as solid
- Conductive as liquid or aqueous as mobile ions carry charge
Covalent molecule
electron distribution, physical properties and conductive properties
- Electrons are shared between atoms, not always shared equally which makes the molecule polarized
- low mpt/bpt, usually gases at room temperature, share e
- cannot conduct electricity as no mobile charged particles
Covalent network
electron distribution, physical properties and conductive properties
- electrons are shared in an ‘infinite network’
- V.V.V high mpt/bpt, brittle
- Diamond and glass cannot conduct electricity but graphite can
Why graphite is conductive
Each carbon atom is covalently bonded to three other carbon atoms the arrangement leaves one electron per carbon atom uninvolved in bonding resulting in delocalized electrons within the layers of graphite. Mobile charged elections facilitate conductivity.
Order of bonding types in mpt/bpt
Covalent network, Ionic, metallic, Covalent molecule
polyatomic ions
2 or more atoms bonded together with net charge
Avogadro’s number
6.022 x 10^23 particles
Law of conservation of mass
Mass is neither created nor destroyed in a chemical reaction. The total mass of the reactants must equal the total mass of the products in a chemical equation.
Electrostatic attraction in metallic bonding
Electrostatic forces between nuclei of atoms to their delocalized electrons
Electrostatic attraction in covalent molecular bonding
Strong intramolecular forces between positive nuclei and shared electrons
Intramolecular forces in covalent network
Strong intramolecular forces throughout the structure, between positive nuclei and shared electrons. Significant energy is required to break these bonds.
Ionic bonds are brittle
When alignment shifts the similar charges repel and the lattice breaks
Intermolecular forces
force of attraction between neighbouring molecules
Reactivity
Measure of how readily a substance interacts with other substances to form new chemical bonds and undergo chemical transformations.
Covalent network structure
lattice of atoms bonded together by covalent bonds in an ‘infinite structure’.
Glass and carbon are Very hard and rigid structure from tightly packed atoms makes structure brittle.
Allotrope
Different structural form of the same element. Allotropes of carbon are diamond and graphite.`
Cdiamond
Each carbon bonded to 4 other carbons, not conductive as no free mobile charge
Cgraphite
Each carbon bonded to three other carbons, 1 spare electrons means graphite is conductive.`
Nanotechnology
Manipulation of matter at nanoscale, at this scale materials exhibit different properties to bulk materials as of high SA/Vol ratio.
Nanoparticles
Very small structures between 1 and 100 nanometres in size
Examples and use of a nonotechnology
Nano silver has antibiotic and fungal properties
Stumbling blocks for the development of nano technology
Not understood the health and environmental risks. If put nano silver into sports clothing could have bad affects on environment when washed.
Isotope properties
Came chem properties, different physical properties
Electron config vs bohrs model
Config = listing electrons in electron shells (2,4)
Bohrs model shows the number of shells, electrons, protons and neutrons
Observations for partial dissolving - excess solid reactant
xx produce xx and some silver granules remain
metallic bonds
electron distribution, physical properties and conductive properties
- delocalised sea of electrons
- high mpt/bpt, lusterous, sea of electrons, malleable
- V.V good conductivity, delocalised electrons allow current to flow
electrostatic attraction in ionic bonding
Strong electrostatic forces between positive ion and negative ion in the crystalline lattice. High electrostatic attraction contributes to high mpt/bpt
