SBI4U - Unit 1 Chemistry of Life Worksheet - ANSWERS 1. Match the following terms to their correct definitions: Polar covalent When electrons are shared equally between two atoms Non-polar covalent When an electron is donated from one atom and given to another, forming a bond. Hydrogen bonding An atom's attraction for electrons in a bond Ionic B When electrons are shared unequally between two atoms Electronegativity Water-fearing Hydrophilic* Intermolecular attraction (not an actual bond) between a H atom and an electronegative element such as O, F or Cl Hydrophobic Water-loving * You have not seen this term yet but will learn about it pretty soon! 2. Identify the following molecules as polar or non-polar and given a reasoning to explain your choice. If the molecule is polar, draw the arrow on the molecule showing the direction that the electrons are being pulled. You can also indicate which atoms are δ+ or δ-. Polar or Molecule Reasoning Non-Polar - symmetrical & contains C/H only - all of the H atoms have same EN Non-Polar and are pulling on C atom in all directions = no EN difference Polar Polar Non-Polar - not symmetrical - EN difference between O and C & OH and C - presence of O (highly EN element) - not symmetrical (bent) - N is more EN than C so presence of EN difference - charges not distributed equally (one side is more positive and other side is more negative) - symmetrical from all angles - contains C and H only - no EN difference (ring is made up of C and H atoms) Polar Non-Polar - not symmetrical - Cl is highly EN, more so than C, so presence of EN different - this makes one side more negative and the other side more positive = unequal distribution of charges - symmetrical (linear) - no EN difference (charges cancelled out) - contains C & H only - F is highly EN, more so than H so electrons are pulled more towards H Polar Polar Polar Non-Polar Non-Polar - presence of O, which is a highly EN element - O is more EN than C = EN difference - this makes one side more negative and the other side more positive = unequal distribution of charges - not symmetrical - Both OH and N are highly EN = EN difference - this makes one side more negative and the other side more positive = unequal distribution of charges - symmetrical - contains C/H only - all of the H atoms have same EN and are pulling on C atom in all directions = no EN difference - symmetrical (linear shape) - although O is highly EN, charges are cancelled out as there is another O on the other side of the central C atom (negative charges pull onto positive C in both directions)
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