BIOL 1201: Exam 1 Study Questions and Answers with Complete Verified Solutions Graded A 2024

BIOL 1201: Exam 1 Study Questions and Answers with Complete Verified Solutions Graded A 2024 A substance that cannot be broken down into other substances by ordinary chemical procedures is a(n) _____. - element Organisms are largely composed of __ elements. - 11 About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter? - carbon, hydrogen, nitrogen, and oxygen What determines solubility? - "like dissolves like" Atom - Smallest unit of matter that retains all the properties of that element What is the mass and charge of protons? - Mass: 1 Dalton Charge: +1 What is the mass and charge of neutrons? - Mass: 1 Dalton No charge What is the mass and charge of electrons? - Mass: close to none (about 1/10000 that of a proton or neutron) Charge: -1 Which subatomic particle(s) always have a positive charge? - protons Atomic Number - equal to the number of protons in an atoms In a neutral atom, the atomic number is equal to... - the number of protons What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons? - 6 From its atomic number of 15, it is possible to predict that phosphorus always has ___. - 15 protons Atomic Mass - the sum of the number of protons and neutrons in an atom Fluorine's atomic number is 9 and its atomic mass is 19. How many neutrons does fluorine have? - 10 neutrons An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many protons does boron have? - 5 protons Changing the number of _____ would change an atom into an atom of a different element. - protons Isotopes - variants of an atom that have different atomic masses due to differing numbers of neutrons What refers to atoms with the same atomic number but different atomic masses? - isotopes True or False: An atom with more neutrons than the atom described in the question above will have a different valence. - False Where are protons located within an atom? - the nucleus Where are neutrons located within an atom? - the nucleus Where are electrons located within an atom? - orbitals, or shells, around the nucleus of an atom What are the names of the first three electron orbitals and how many electrons do each of them contain? - K-shell: 2 electrons L-shell: 8 electrons M-shell: 8 electrons An atom with the atomic number 9 will have _______ electrons in its outermost electron shell. - 7 Electrons always try to be in the ____ orbital or energy shell. - lowest Valence - the number of electrons that either need to be gained or lost to fill the outermost shell with electrons What is significant about valence? - Valence predicts the number of bonds that atoms will form An atom with the atomic number 15 has a valence of __. - 3 Valence Electrons - electrons in the outermost shell of an atom What is the difference between valence and valence electrons? - Valence is the NUMBER of electrons that either need to be gained or lost to fill the outermost shell with electrons, while valence electrons are the ELECTRONS in the outermost shell of an atom When are atoms the most stable and nonreactive? - Atoms are stable and nonreactive when their outer electron shells are full. Why do atoms attempt to either gain or lose electrons? - Atoms attempt to either lose or gain electrons in order to fill their outer shells and become stable Chemical bonds are the result of ____________. - electrical attractions between atoms that either gain, lose, or share electrons Ionic Bonds - bonds that are the result of very strong electrical attractions, where electrons are either lost or gained An ionic bond involves _____. - an attraction between ions of opposite charge Ionic bonds are strongest when _____. - they are dry Atoms with the same number of protons but with different electrical charges _____. - are different ions In salt, what is the nature of the bond between sodium and chlorine? - ionic Covalent Bonds - bonds that are the result of electrical attractions that are not so strong, where the electrons are shared If electrons are shared equally, then the bond is known as a ________. - pure covalent bond, or non -polar covalent bond If electrons are shared unequally, then the bond is known as a _____. - polar covalent bond What happens to the electrons in a polar covalent bond? - The more electronegative atom has the electrons more than the other atom, creating a slight charge negative charge where the electrons spend the most time and a slight positive charge where the electrons spend the least amount of time. These opposing charges hold the molecule together. When are covalent bonds the strongest? - in water A(n) _____ refers to two or more atoms held together by covalent bonds. - molecule Compound - a substance consisting of two or more different atoms, in specific proportions, bonded together in a specific pattern