2.1 Atoms, Isotopes, Ions, and Molecules: The Building Blocks

Question 1

Isotopes

Answer 1

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

Question 2

Elements

Answer 2

unique substances that cannot be broken down into smaller substances

Question 3

Nucleus

Answer 3

core of an atom; contains protons and neutrons

Question 4

Neutron

Answer 4

uncharged particle that resides in the nucleus of an atom

Question 5

Proton

Answer 5

positively charged particle that resides in the nucleus of an atom

Question 6

Electron

Answer 6

negatively charged subatomic particle that resides outside of the nucleus in the electron orbital

Question 7

Atomic Number

Answer 7

number of protons in an atom

Question 8

Mass Number

Answer 8

total number of protons and neutrons in an atom

Question 9

Atomic Mass

Answer 9

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

Question 10

Periodic Table

Answer 10

organizational chart of elements (118 elements; 98 naturally occurring)

Question 11

Chemical Reactivity

Answer 11

the ability to combine and to chemically bond with each other

Question 12

Octet Rule

Answer 12

atoms are most stable when they hold 8 electrons in their outermost shell

Question 13

Valence Shell

Answer 13

outermost shell of an atom

Question 14

Inert Gases

Answer 14

element with filled outer electron shell that is unreactive with other atoms

Question 15

Ions

Answer 15

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

Question 16

Electron Orbitals

Answer 16

how electrons are spatially distributed surrounding the nucleus

Question 17

Electron Configuration

Answer 17

arrangement of electrons in an atomic shell

Question 18

Chemical Bonds

Answer 18

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

Question 19

Chemical Reaction

Answer 19

process leading to the rearrangement of atoms in molecules

Question 20

Reactants

Answer 20

molecule found of the left side of a chemical equation

Question 21

Products

Answer 21

molecule found on the right side of a chemical equation

Question 22

Balanced Chemical Equation

Answer 22

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

Question 23

Compounds

Answer 23

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

Question 24

Reversible Reactions

Answer 24

bi-directional; products may turn into reactants if concentration is great enough

Question 25

Irreversible Reactions

Answer 25

unidirectional; forms products

Question 26

Equilibrium

Answer 26

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

Question 27

Law of Mass Action

Answer 27

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

Question 28

Cation

Answer 28

positive ion formed by an atom losing one or more electrons

Question 29

Anion

Answer 29

negative ion formed by an atom gaining one or more electrons

Question 30

Electron Transfer

Answer 30

movement of electrons from one element to another

Question 31

Ionic Bonds

Answer 31

chemical bond that forms between ions with opposite charges

Question 32

Electrolytes

Answer 32

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

Question 33

Covalent Bonds

Answer 33

bond formed when electrons are shared between atoms

Question 34

Polar

Answer 34

unequally shared electrons

Question 35

Nonpolar

Answer 35

equally shared electrons

Question 36

Electronegativity

Answer 36

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

Question 37

Hydrogen Bond

Answer 37

weak bond between slightly positive hydrogen atoms and slightly negative atoms in other molecules

Question 38

van der Waals interactions

Answer 38

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