Electronegativity and Chemical Bonding

Electronegativity is the tendency of an element to attract a pair of electrons, measured using the Pauling scale.

A covalent bond forms when the energy of the bonded atoms is lower than that of the separate atoms.

Electronegativity differences determine the type of bond formed: nonpolar covalent, polar covalent, or ionic.

<p>Nonpolar covalent bonds involve the equal sharing of electron pairs without significant charges on atoms.</p> Signup and view all the answers

<p>For polar covalent bonds, the difference in electronegativity is generally between 0.5 and 2.0.</p> Signup and view all the answers

<p>Chlorine molecules (Cl2) exhibit nonpolar covalent bonds since both chlorine atoms have the same electronegativity.</p> Signup and view all the answers

<p>Single bonds involve one pair of shared electrons, double bonds two pairs, and triple bonds three pairs.</p> Signup and view all the answers

<p>Hydrogen bonding is a strong type of dipole-dipole attraction involving hydrogen atoms bonded to highly electronegative atoms.</p> Signup and view all the answers

<p>A delta positive (δ+) charge indicates a partial positive charge on an atom due to unequal sharing of bonding electrons.</p> Signup and view all the answers

<p>A significant difference in electronegativity (&gt; 2) typically leads to the formation of ionic bonds, while a smaller difference results in covalent bonds.</p> Signup and view all the answers

<p>Ionic compounds are usually solid at normal temperatures, have high aqueous solubility, and consist of cations and anions.</p> Signup and view all the answers

<p>A delta negative (δ-) charge signifies a partial negative charge on an atom due to its higher electronegativity in a bond.</p> Signup and view all the answers

<p>The bond type between two nonmetals is determined by the difference in their electronegativities, leading to either polar covalent or nonpolar covalent bonds.</p> Signup and view all the answers

<p>The values represent the electronegativity of different atoms, with higher values indicating a stronger ability to attract electrons.</p> Signup and view all the answers

<p>Ionic compounds form between elements with a large difference in electronegativity, typically between metals on the left and non-metals on the right.</p> Signup and view all the answers

<p>Lone pairs can create regions of negative charge, influencing the distribution of electron density and ultimately affecting molecular polarity.</p> Signup and view all the answers

<p>Partial charges occur when atoms in a molecule have different electronegativities, leading to unequal sharing of electrons and creating regions of partial positive and negative charges.</p> Signup and view all the answers

<p>In a covalent bond, electrons are shared between atoms, whereas in an ionic bond, electrons are completely transferred from one atom to another.</p> Signup and view all the answers

<p>The direction of the vector points towards the more polar atom, while the length indicates the degree of polarity in the bond.</p> Signup and view all the answers

<p>The parallelogram method assists in vector addition, allowing for the calculation of net dipoles and thus helps in determining the overall molecular polarity.</p> Signup and view all the answers

<p>C2H2Cl2 can have different spatial arrangements of Cl and H atoms, leading to varied dipole moments that can either cancel out or not, resulting in polar or non-polar molecules.</p> Signup and view all the answers

<p>A net dipole moment of zero indicates that the molecule is non-polar, as the individual bond dipoles effectively cancel each other out.</p> Signup and view all the answers

<p>Electronegativity values help identify the more polar atom in a bond, as greater differences in electronegativity contribute to stronger dipoles.</p> Signup and view all the answers

<p>Cations become smaller, more highly charged, and more strongly polarising as you move from left to right across a period.</p> Signup and view all the answers

<p>Anions become larger and more polarisable down a group because the electron cloud becomes more distorted as the ionic radius increases.</p> Signup and view all the answers

<p>The polarising power of diagonal neighbours, such as Li+ and Mg2+, is similar despite differences in size.</p> Signup and view all the answers

<p>NaCl has less polarisation compared to MgCl2 due to Mg2+'s higher charge, resulting in a stronger distortion of the anion's electron cloud.</p> Signup and view all the answers

<p>An electric dipole refers to a pair of equal and opposite charges separated by a distance, resulting from partial charges within the compound.</p> Signup and view all the answers

<p>Partial charges arise from small shifts in the distribution of electrons around the ions, leading to unequal charge distribution.</p> Signup and view all the answers

<p>Cations become larger and less polarising down a group due to increased electron shielding and distance from the nucleus.</p> Signup and view all the answers

<p>Electronegativity differences drive the formation of ionic bonds, influencing the extent to which anions polarise due to cation attraction.</p> Signup and view all the answers

<p>Higher charged cations exhibit greater polarising ability, as their increased positive charge distorts the electron cloud of nearby anions.</p> Signup and view all the answers

<p>Anions become smaller and less polarisable from left to right across a period due to an increase in effective nuclear charge.</p> Signup and view all the answers

<p>A polar bond is a covalent bond between atoms with partial electric charges, while a polar molecule has a non-zero electric dipole moment.</p> Signup and view all the answers

<p>A molecule can be nonpolar if the shape allows the dipoles of individual polar bonds to point in opposite directions, canceling each other out.</p> Signup and view all the answers

<p>The dipole moment (μ) indicates the polarity of a molecule, with a non-zero value signifying a polar molecule.</p> Signup and view all the answers

<p>CO2 has a dipole moment of 0 because its linear shape allows the dipoles from the polar bonds to cancel each other out.</p> Signup and view all the answers

<p>Dichloromethane has a molecular shape that leads to a net dipole moment, making it polar despite having polar bonds.</p> Signup and view all the answers

<p>Vectors represent polar bonds' magnitude and direction, and can be used to determine the net polarity of a molecule by adding or subtracting them.</p> Signup and view all the answers

<p>NaCl has a dipole moment of 9.00, indicating it is a highly polar compound due to the significant difference in electronegativity between Na and Cl.</p> Signup and view all the answers

<p>Methane (CH4) is nonpolar because it has symmetrical geometry, allowing the dipoles from the polar bonds to cancel each other out.</p> Signup and view all the answers

<p>BF3 has a dipole moment of 0, indicating that it is a nonpolar molecule despite having polar bonds.</p> Signup and view all the answers