unit 1

• Block organisation: s < p < d < f
• Aufbau Principle: Electrons fill sub-levels from the lowest energy level upwards
• Pauli exclusion principle states that the maximum number of electrons in an orbital is two and if there are two electrons in an orbital, they must have opposite spins
• Hund’s rule states that if more than one orbital in a sub-level is available, electrons occupy different orbitals with parallel spins
• A mixture contains more than one element or compound with no fixed ratio that is not chemically bonded together. The components of a mixture can be separated by physical methods
• Mixtures can be homogeneous (uniform composition) or heterogeneous (non-uniform composition)
• A pure substance can be elements or compounds
• Components of a homogeneous mixture are in the same state, spread evenly through the mixture, and cannot be individually identified
• Examples of a homogeneous mixture: air (gases are mixed evenly), sugar dissolved in water (solid dissolves evenly through liquid)
• Components of a heterogeneous mixture are not in the same state, not spread evenly through the mixture, and can be individually identified
• Examples of a heterogeneous mixture: oil and water (2 layers observed), sand mixed with water (solid sits at the bottom of the liquid)
• Gravity filtration is used to separate an undissolved solid from a mixture of the solid and a liquid or solution. Centrifugation can also be used for this mixture. Suction Filtration using the Buchner Funnel is used to separate solid particles from a liquid under gravity at atmospheric pressure or under reduced pressure for finer particles
• Gravity filtration is preferred when the filtrate is retained, and suction filtration is preferred when the solid is retained
• Crystallisation is used to separate a dissolved solid from a solution when the solid is much more soluble in hot solvent than in cold
• Recrystallisation involves dissolving an impure solid in a suitable solvent, then allowing it to cool slowly so that the solid separates out as crystals
• Simple Distillation is used to separate a liquid and soluble solid from a solution or a pure liquid from a mixture of liquids
• Paper Chromatography is used to separate substances with different solubilities in a given solvent
• Dissolution involves adding a mixture to water or organic solvent, then removing components through filtration
• Relative atomic mass (Ar) is the average mass of an element's naturally occurring isotopes compared to 1/12th of an atom of carbon-12
• Mass Spectrometer is an analytical technique that measures the mass-to-charge ratio of ions and can be used to determine the RAM of an element and the structure of a compound
• VIADD stands for vaporisation, ionisation, acceleration, deflection, and detection in Mass Spectrometry
• The y-axis of a mass spectra shows the relative percentage abundance of ions, and the x-axis shows the mass/charge ratio of ions
• Trends in a Mass Spectrometry: the amount of deflection depends on the mass of the ion, lighter ions are deflected less than heavy ones
• Steps in a Mass Spectrometry involve vaporizing the sample, bombarding it with electrons, accelerating the ions, deflecting them with a magnetic field, and detecting the pattern of deflection
• Inside a Mass Spectrometry, some molecular ions break down to produce fragments, giving useful information about the compound's structure
• The mass-to-charge ratio of the molecular ion is the same as the relative molecular mass of the compound
• Electrons exist within an atom within discrete energy levels, each given a principal quantum number (n)
• Wavelength is the distance between two successive crests, measured in meters. Frequency is the number of waves that pass a certain point in one second, measured in hertz
• Electromagnetic radiation can be described in terms of particles called photons. It can be continuous or in a line emission spectrum
• Flame tests are used to identify elements based on their line emission spectrum
• Calculating the energy of a photon involves the equation E = v * h, where h is Plank’s constant measured in joules a second (6.63 x 10-34Js)
• Solids have particles with low energy that vibrate around a fixed point with vibrational and rotational motion
• Liquids have particles with a large amount of energy that can move freely around each other with vibrational, rotational, and translational motion
• Gases have particles with large amounts of energy that move rapidly and randomly into available space with vibrational, rotational, and translational motion
• The Kelvin scale is used to measure temperature, where absolute zero (0K) is the lowest possible temperature as all motion of particles has stopped
• Converting Celsius into Kelvin involves adding 273
• Physical Changes: Exothermic changes include condensation and freezing. Endothermic changes include melting and vaporization
• Evaporation can occur at any temperature and only at the surface of a liquid. Boiling occurs at fixed temperatures when the vapor pressure equals the external pressure
• Characteristics of matter: made up of particles, occupies a volume in space, has mass, particles are in constant motion
• Relative mass and charge of protons: +1. Relative mass and charge of electrons: very small, -1. Relative mass and charge of neutrons: +1, 0