what are four major elements found in chemicals that comprise human body? a. nitrogen, oxygen, calcium, sodium b. hydrogen, carbon, phosphorus, calcium c. carbon, hydrogen, oxygen and nitrogen d. oxygen, nitrogen, potassium, calcium e. potassium, phosphorus, sodium, hydrogen - ANS-c. carbon, hydrogen, oxygen and nitrogen three types of subatomic particles that are important for understanding chemical reactions in human body are a. neutrons, quarks, & muons b. protons, neutrons, and electrons c. muons, positons, & neutrons d. electrons, quarks, & protons e. positons, protons, & neutrons - ANS-b. protons, neutrons, and electrons which of the following subatomic particles has/have a neutral charge? a. neutron b. electron c. proton d. both neutron & electron e. all of these choices - ANS-a. neutron what region of an atom contains the protons & neutrons? a. cloud b. nucleus c. element d. ring e. shell - ANS-b. nucelus the number of protons in an atom is represented by an element's a. mass number b. atomic number c. atomic mass d. valence number e. none of these choices - ANS-atomic number the nucleus of unstable _____ of an element will decay leading to emission of radiation a. compounds b. cations c. anions d. isotopes e. molecules - ANS-d. isotopes this refers to a weighted average of the atomic weights of all naturally occurring isotopes of an element a. mass number b. atomic number c. atomic mass d. ionic mass e. covalent mass - ANS-c. atomic mass briefly describe the octet rule - ANS-one atom is more likely to combine w/ another atom if doing so will leave both atoms w/ eight electrons in their valence shells which of following subatomic particles are shared by two atoms to form covalent bonds? 1. neutron 2. electron 3. proton a. 1 only b. 2 only c. 3 only d. 2 & 3 only e. 1, 2 & 3 - ANS-b. 2 only what is name given to a negatively charged atom? a. superoxide b. isotope c. catalyst d. anion e. cation - ANS-d. anion chemical that can conduct electrical current when dissolved in water is called a(n) a. isotope b. isomer c. compound d. electrolyte e. valence molecule - ANS-d. electrolyte which type of chemical bond involves sharing of valence electron pairs between two atoms? a. covalent b. ionic c. hydrogen d. atomic e. electronic - ANS-a. covalent chemical bonds formed between oxygen & hydrogen atoms making up water molecule are called a. nonpolar covalent bonds b. polar covalent bonds c. hydrogen bonds d. ionic bonds e. atomic bonds - ANS-b. polar covalent bond describe a hydrogen bond - ANS-hydrogen bonds form between a hydrogen atom that has partial positive charge & another atom, like oxygen or nitrogen, carrying partial negative charge which relatively weak type of bond helps stabilize the three dimensional structure of large molecules like proteins & DNA? a. nonpolar covalent b. polar covalent c. hydrogen d. ionic e. atomic - ANS-c. hydrogen chemical reaction involves interactions between the ____________ of two different atoms a. neutrons b. protons c. isotopes d. valence electrons e. ions - ANS-d. valence electrons which term is defined as the capacity to do work? a. metabolism b. electrolytes c. chemical reaction d. concentration e. energy - ANS-e. energy describe the law of conservation of energy - ANS-energy cannot be created or destroyed but it may be converted from one form to another form. which type of chemical reaction will absorb more energy than it releases? a. exergonic b. endergonic c. potential d. kinetic e. activation - ANS-b. endergonic an enzyme acts to a. raise the activation energy needed to start the reaction b. lower the activation energy needed to start the reaction c. convert the activation energy into potential energy d. convert the activation energy into kinetic energy e. stop a chemical reaction - ANS-b. lower the activation energy needed to start the reaction list three factors that increase the rate of chemical reactions - ANS-three factors that increase reaction rates are presence of enzymes (catalysts), increased concentration of reactants, & increased temperature