Question

1. the major function of potassium is to: a. serve as a salt in bones and teeth b. play a role in nerve impulse transmissions and muscle contractions c. make functional thyroid hormones d. influence the ph of body fluids e. exist as the most abundant extracellular cation 8. which of the following is the role of magnesium: a. it is present in bone, and is an important cofactor for enzyme activity in a of metabolic reactions b. it is needed to make functional thyroid hormones c. it is a component of the functional hemoglobin molecule that transports o within red blood cells, as well as a component of some enzymes d. it is the major extracellular cation in its ionic form, and is important for w balance, conduction of nerve impulses, and muscle contraction e. it is a major extracellular anion in its ionic form 9. an atom has 6 protons, 8 neutrons, and 6 electrons. its atomic mass is: a. 2 b. 6 c. 8 d. 14 e. 20 10. the atomic number of an atom reveals the number of: a. electrons in the atomic nucleus b. protons in the atomic nucleus c. protons plus neutrons d. protons plus electrons e. neutrons plus electrons 11. isotopes have different numbers of ______; thus they also have different a. protons; atomic numbers b. neutrons; atomic masses c. electrons; atomic numbers d. protons; atomic masses e. neutrons; atomic numbers 12. an atom that has lost two electrons is called a(n): a. isotope b. anion c. radioisotope d. cation e. proton

Explanation:

• Question 7: Potassium is crucial for nerve impulse transmission and muscle contractions. Calcium is related to bones and teeth, iodine for thyroid - hormone production, bicarbonate and other ions for pH regulation, and sodium is the most abundant extracellular cation.
• Question 8: Magnesium is present in bone and acts as a co - factor for enzyme activity in many metabolic reactions. Iodine is needed for thyroid hormones, iron is in hemoglobin, sodium is the major extracellular cation, and there are no major extracellular anions among the options that match magnesium.
• Question 9: Atomic mass is the sum of protons and neutrons. Given 6 protons and 8 neutrons, atomic mass = 6 + 8=14.
• Question 10: The atomic number of an atom is equal to the number of protons in the atomic nucleus.
• Question 11: Isotopes have the same number of protons but different numbers of neutrons, resulting in different atomic masses.
• Question 12: An atom that loses electrons becomes positively charged and is called a cation. An anion gains electrons, an isotope has a different number of neutrons, a radioisotope is a radioactive isotope, and a proton is a sub - atomic particle.

Answer:

1. B. play a role in nerve impulse transmissions and muscle contractions
2. A. it is present in bone, and is an important cofactor for enzyme activity in a of metabolic reactions
3. D. 14
4. B. protons in the atomic nucleus
5. B. neutrons; atomic masses
6. D. cation