Chapter 2 - Mader Biology All Possible Questions and Answers with complete solution

compound - substance formed by the chemical combination of two or more elements in definite proportions calorie - amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius acid - any compound that increases the number of hydronium ions when dissolved in water atom - the basic unit of matter atomic mass - the weighted average of the masses of the isotopes of an element atomic number - the number of protons in an atom atomic symbol - a one or two letter abbreviation for an element base - a substance that reduces the hydrogen ion concentration of a solution buffer - compound that prevents sharp, sudden changes in pH covalent bond - a bond formed when atoms share one or more pairs of electrons electron - negatively charged particle; located outside the atomic nucleus electronegativity - the ability of an atom to attract electrons when the atom is in a compound electron shell - an energy level of electrons at a characteristic average distance from the nucleus of an atomelement - pure substance that consists entirely of one type of atom formula - a mathematical relationship or rule expressed in symbols hydrogen ion (H+) - hydrogen atom that has lost its electron and therefore bears a positive charge hydrophilic - having an affinity for water