CLEP Biology (1.1.1) Simple Chemical Reactions and Bonds With complete verified solutions

nonpolar covalent bond

type of covalent bond that forms between atoms when electrons are shared equally between them

How many neutrons do carbon-12 and carbon-13 have, respectively?

Carbon-12 has six neutrons. Carbon-13 has seven neutrons.

An atom may give, take, or share electrons with another atom to achieve a full valence shell, the most stable electron configuration. How many electrons do elements in group 1 need to lose in order to achieve a stable electron configuration? How many electrons do elements in groups 14 and 17 need to gain to achieve a stable configuration?

Elements in group 1 need to lose one electron to achieve a stable electron configuration. Elements in groups 14 and 17 need to gain four and one electrons, respectively, to achieve a stable configuration.

If xenon has an atomic number of 54 and a mass number of 108, how many neutrons does it have?

54

27

100

108

54

Atoms that vary in the number of neutrons found in their nuclei are called ________.

isotopes

Potassium has an atomic number of 19. What is its electron configuration?

shells 1 and 2 are full, and shell 3 has nine electrons

shells 1, 2 and 3 are full and shell 4 has three electrons

shells 1, 2 and 3 are full and shell 4 has one electron

shells 1, 2 and 3 are full and no other electrons are present

shells 1, 2 and 3 are full and shell 4 has one electron

Which type of bond represents a weak chemical bond?

hydrogen bond

atomic bond

covalent bond

nonpolar covalent bond

hydrogen bond

What makes ionic bonds different from covalent bonds?

Ionic bonds are created between ions. The electrons are not shared between the atoms, but rather are associated more with one ion than the other. Ionic bonds are strong bonds, but are weaker than covalent bonds, meaning it takes less energy to break an ionic bond compared with a covalent one.

Why are hydrogen bonds and van der Waals interactions necessary for cells?

Hydrogen bonds and van der Waals interactions form weak associations between different molecules or within different regions of the same molecule. They provide the structure and shape necessary for proteins and DNA within cells so that they function properly.

anion

negative ion that is formed by an atom gaining one or more electrons

negative ion that is formed by an atom gaining one or more electrons

atom

atom

the smallest unit of matter that retains all of the chemical properties of an element

atomic mass

atomic mass

calculated mean of the mass number for an element's isotopes

atomic number

total number of protons in an atom

atomic number

total number of protons in an atom

balanced chemical equation

statement of a chemical reaction with the number of each type of atom equalized for both the products and reactants

balanced chemical equation

statement of a chemical reaction with the number of each type of atom equalized for both the products and reactants

cation

cation

positive ion that is formed by an atom losing one or more electrons

chemical bond

interaction between two or more of the same or different atoms that results in the formation of molecules

chemical reaction

process leading to the rearrangement of atoms in molecules

chemical reactivity

the ability to combine and to chemically bond with each other

compound

substance composed of molecules consisting of atoms of at least two different elements

covalent bond

type of strong bond formed between two of the same or different elements; forms when electrons are shared between atoms

electrolyte

ion necessary for nerve impulse conduction, muscle contractions and water balance

electron orbital

how electrons are spatially distributed surrounding the nucleus; the area where an electron is most likely to be found

electron

negatively charged subatomic particle that resides outside of the nucleus in the electron orbital; lacks functional mass and has a negative charge of -1 unit

electron transfer

movement of electrons from one element to another; important in creation of ionic bonds

electron configuration

arrangement of electrons in an atom's electron shell (for example, 1s2 2s2 2p6)

electronegativity

ability of some elements to attract electrons (often of hydrogen atoms), acquiring partial negative charges in molecules and creating partial positive charges on the hydrogen atoms

element

one of 118 unique substances that cannot be broken down into smaller substances; each element has unique properties and a specified number of protons

equilibrium

steady state of relative reactant and product concentration in reversible chemical reactions in a closed system

hydrogen bond

weak bond between slightly positively charged hydrogen atoms to slightly negatively charged atoms in other molecules

inert gas

(also, noble gas) element with filled outer electron shell that is unreactive with other atoms

ion

atom or chemical group that does not contain equal numbers of protons and electrons

ionic bond

chemical bond that forms between ions with opposite charges (cations and anions)

irreversible chemical reaction

chemical reaction where reactants proceed uni-directionally to form products

isotope

one or more forms of an element that have different numbers of neutrons

law of mass action

chemical law stating that the rate of a reaction is proportional to the concentration of the reacting substances

mass number

total number of protons and neutrons in an atom

matter

anything that has mass and occupies space

molecule

two or more atoms chemically bonded together

neutron

uncharged particle that resides in the nucleus of an atom; has a mass of one amu

nucleus

core of an atom; contains protons and neutrons

octet rule

rule that atoms are most stable when they hold eight electrons in their outermost shells

orbital

region surrounding the nucleus; contains electrons

periodic table

organizational chart of elements indicating the atomic number and atomic mass of each element; provides key information about the properties of the elements

polar covalent bond

type of covalent bond that forms as a result of unequal sharing of electrons, resulting in the creation of slightly positive and slightly negative charged regions of the molecule

product

molecule found on the right side of a chemical equation

proton

positively charged particle that resides in the nucleus of an atom; has a mass of one amu and a charge of +1

radioisotope

isotope that emits radiation composed of subatomic particles to form more stable elements

reactant

molecule found on the left side of a chemical equation

reversible chemical reaction

chemical reaction that functions bi-directionally, where products may turn into reactants if their concentration is great enough

valence shell

outermost shell of an atom

van der Waals interaction

very weak interaction between molecules due to temporary charges attracting atoms that are very close together