Chapter 2

Question 1

alpha particle

Answer 1

positively charged
particle consisting of two protons and two neutrons

Question 2

anion

Answer 2

negatively charged atom or molecule (contains more electrons than protons)

Question 3

atomic mass

Answer 3

average mass of atoms of an element, expressed in amu

Question 4

atomic mass unit (amu)

Answer 4

unit of mass equal to 1/12 of the mass of a carbon-12 atom

Question 5

atomic number (Z)

Answer 5

number of protons in the nucleus of an atom

Question 6

cation

Answer 6

positively charged atom or molecule

Question 7

chemical symbol

Answer 7

one-, two-, or three-letter
abbreviation used to represent an element or its atoms

Question 8

Dalton (Da)

Answer 8

alternative unit equivalent to the
atomic mass unit

Question 9

electron

Answer 9

negatively charged, subatomic particle of relatively low mass located outside the nucleus

Question 10

empirical formula

Answer 10

formula showing the composition of a compound given as the simplest whole number ratio of atoms

Question 11

ion

Answer 11

electrically charged atom or molecule (contains
unequal numbers of protons and electrons)

Question 12

isomer

Answer 12

same formula but different structure

Question 13

isotope

Answer 13

same number of protons but different number of neutrons

Question 14

law of constant composition

Answer 14

(aka law of definite proportions) - all samples of a pure compound contain the same elements in the same proportions by mass

Question 15

law of multiple proportions

Answer 15

when two elements react to form more than one compound, a fixed mass of one element will react with masses of the other element in a ratio of small whole numbers

Question 16

mass number

Answer 16

sum of the numbers of neutrons and protons in the nucleus of an atom

Question 17

molecular formula

Answer 17

formula indicating the
composition of a molecule of a compound and giving the actual number of atoms of each element in a molecule of the compound.

Question 18

spatial isomer

Answer 18

compound in which the relative orientations of the atoms in space differs

Question 19

structural formula

Answer 19

shows the atoms in a molecule and how they are connected

Question 20

structural isomer

Answer 20

same molecular formula but different structure and thus different properties

Question 21

average mass formula

Answer 21

sum of : (fractional abundance * isotopic mass)

Question 22

how to find molecular formula from empirical formula

Answer 22

(molar mass molecular / molar mass empirical) = #

Multiply that number through

Question 23

volume of a cylinder

Answer 23

V = (pi)(radius squared)(height)