Elements of Life

• What does the nucleus consist of?

  protons and neutrons giving an overall positive charge
• What is the relative charge of P, E, N?

  P = +1

  N = 0

  E = -1
• What is the relative mass of P, E, N?

  P = 1

  E = 1/1840

  N = 1
• What’s an ion?

  When an atom loses or gains an electron. This means its no longer neutral and will have an overall charge
• What’s an isotope?

  Atoms of the same element with the same atomic number but a different number of neutrons so different mass number
• What’s relative atomic mass?

  The mean mass of an atom of an element, relative to 1/12 of the mean of an atom of the carbon-12 isotope
• What’s the isotopic mass?

  The mass of an isotope relative to 1/12 of the mean mass of an atom of the carbon-12 isotope
• What’s relative molecular mass?

  The mean mass of a molecule of a compound, relative to 1/12 of the mean mass of an atom of the carbo-12 isotope
• What’s a mole?

  Unit of measurement for substances
• What is avogadros constant?

  6.02 x 10^23
• What is molar mass?

  Mass per mole and has units g mol-1
• What’s molar gas volume?

  the gas volume per mile and has units dm3 mol-1
• What is the empirical formula?

  the simplest whole number ratio of atoms of each element present in a compound
• Water of Crystallisation is water that is part of the crystalline structure. The molecules stoichiometrically chemically bonded into the crystal structure
• An anhydrous substance contains no water of crystallisation

  Hydrated substance fountains water of crystallisation
• What is the

  formula for % yield

  % yield = Experimental mass/theoretical mass x100
• What’s the formula for percentage composition?

  % composition = Mr of element/Mr of compound X100
• How do you calculate concentration?

  Number of moles/Volume
• What is the formula for concentration (g dm-3)?

  Mass/Volume
• What are the maximum electrons that can be held in the first 4 orbitals (s,p,d,f)?

  2, 6, 10, 14
• What happens in a fusion reaction?

  Two lighter nuclei join to give a single heavier nucleus. Required high temp and pressure
• What is ionic bonding?

  An electrostatic attraction between positive and negative ions
• Between what atoms do ionic bonding occur?

  metals and non metals. transferred from metal to non metal to achieve full outer shells
• When the electrons are transferred it creates charged particles called ions. Oppositely charged ions attract through electrostatic forces to form a giant ionic lattice.
• What is a covalent bond?

  the string electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms between 2 metals
• What’s a dative covalent bond?

  When both of the electrons in the shared pair are supplied from a single atom. This is indicated using an arrow from the lone electron pair
• Simple covalent


  consist of covalently bonded molecules held together with intermolecular forces. Shape is determined by the number of electron pairs around the central atom and repulsion between them. Each pair naturally repel each other so the largest bond angle possible exists
• Lone pair repulsion

  Any lone pairs around the central atom provide additional repulsive forces. For every lone pair present the bond angle between covalent bonds is reduced by 2.5°
• What is the bond length?

  The average distance between two nuclei in a covalent bond
• What is a bond angle?

  The angle between two covalent bonds from the same atom
• Bond angles and naming

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• Bond angles and naming

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• Giant covalent structures

  Macro molecular covalent substances are covalently bonded into a giant lattice structure. Each atom has multiple covalent bonds which are very strong giving the substance a very high melting point
• Diamond

  A macro molecular structure made up of carbon atoms each bonded to four further carbons. This forms a rigid tetrahedral structure making it one of the hardest strongest materials
• Graphite

  Another macromolecular structure made of carbon atoms. However in graphite each carbon is bonded to 3 others in flat hexagonal sheets. Only 1 delocalised electron per carbon atom. These can move freely allowing graphite to conduct electricity. Therefore it can be used in an electrode. The intermolecular forces are weak and can slide meaning it’s a lubricant
• Metallic bonding

  Consists of a giant lattice of positively charged ions surrounded by a sea of delocalised electrons. Very strong electrostatic forces of attraction between oppositely charged particles.

  The greater the charge on +ve the stronger the attractive force since more electrons r released

  Larger ions produce a weaker attraction bc greater atomic radius
• Metallic structure

  Good conductors. Delocalised electrons able to move and carry a flow. Malleable because uniform layers of positive ions are able to slide over one another. Delocalised electrons prevent fragmentation as they can move around lattice
• Metallic structure

  Electrostatic forces between +ve ions and delocalised electrons are v strong and therefore require a lot of energy to overcome. High melting points and nearly always solid at room temp. Mercury is the only exception as it’s liquid
• What order is the period table have elements in?

  increasing proton number
• All elements in a period have the same number of shells