Karteikarten
bond
Karten in diesem Stapel (20)
- 1There are two important, linked parameters in relation to covalent bonding What are they? Explain them.Bond length: which is a measure of the distance between the two bonded nuclei.
Bond strength: which is usually described in terms of bond enthalpy, discussed later in Topic 5, and is effectively a measure of the energy required to break the bond. - 2atomic radius increases going ____ a groupdown
- 3This data confirms that triple bonds are _____ and _____ than double bonds, which are, in turn, _____ and _____ than single bondsshorter, stronger, shorter, stronger
- 4How can bond strength influence reactivity of a compound?The molecules in liquids and gases are in random motion, so they are constantly colliding with each other. A reaction only happens between molecules when a collision occurs with enough energy to break bonds in either or both molecules.
- 5If the difference in electronegativity value is greater than around _, then the bond is ionic A difference in electronegativity value of _ means the bond is non-polar covalent. A difference in electronegativity between _ and _ means that the bond is polar covalent.-1.8
-0
-0, 1.8 - 6Polar covalent bonds are covalent bonds that have some degree of ___ characterionic
- 7The larger the electronegativity difference between the atoms the greater ......the polarisation of the bond, and the greater its ionic character
- 8how does electronegativity vary in relation to the position of an element in the Periodic Table?
- 9The polarity of the H-X bond _____ as you descend the groupdecreases
- 10Outline the effect of polar bonds in a molecule.The presence of polar bonds in a molecule has a significant effect on its properties. Effectively, the partial separation of charges introduces some ionic nature into covalent bonds, so the more polar the bond, the more like an ionic compound the molecule behaves
- 11Explain temporary dipolesTemporary dipoles are caused by the instantaneous, random fluctuations in the electron density in a molecule or an atom. Over an extended period of time, the electron density is spread evenly around the nucleus or nuclei. However, at a given instant, the electron density distribution may not be symmetrical, thus giving the atom or molecule a temporary dipole. A dipole is a separation of charge.
- 12Explain what the formation of a temporary dipole can affect and what this is.The formation of a temporary dipole in one atom or molecule can affect the distribution of electron density in a neighbouring atom or molecule, causing displacement and the formation of another temporary dipole. This process is termed induction. The newly formed dipole an induced dipole. The formation of induced dipoles rapidly transmits itself through a liquid or solid. These forces of attraction between temporary or induced dipoles are known as London (dispersion) forces.
- 13what is polarizability?Polarizability is a measure of the ease with which the electron density of an atom or molecule can be distorted by an electric field.
- 14Larger molecules or atoms are more polarizable than smaller ones. Why? Explain.This is because they have a greater volume occupied by the electrons, and therefore there is greater scope for distortion. The greater the polarization, larger the size of the temporary or induced dipole. Hence, London forces tend to increase with relative atomic or relative molecular mass.
- 15London (dispersion) forces are the only forces that exist between ___ moleculesnon-polar
- 16Permanent dipole?It results in opposite charges on neighbouring molecules attracting each other, generating a force known as a dipole-dipole attraction
- 17A dipole–dipole force exists between ....... because.....polar molecules because the positive end of the dipole of one molecule electrostatically attracts the negative end of the dipole of another molecule
- 18Hydrogen bonding is a particular form of .....strong permanent dipole–dipole attraction between molecules
- 19When does hydrogen bonding occur?It occurs between molecules that contain a hydrogen atom covalently bonded to a fluorine, oxygen or nitrogen atom: three atoms that are small and highly electronegative.
- 20The essential requirements for the formation of a hydrogen bond are .....a hydrogen atom directly attached to oxygen, nitrogen or fluorine, and
a lone pair of electrons on the electronegative atom of the adjacent molecule
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- International Baccalaureate (IB) Chemistry (4- Bonding ) Karteikarten am bond, erstellt von Lizzy Crockatt am 07/02/2017.
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- Lizzy Crockatt
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