unit 2 - atoms, molecules + ions

Question 1

Dalton’s atomic theory

Answer 1

set of postulates that established the fundamental properties of atoms

Question 2

isotope

Answer 2

atoms that contain the same number of protons but different numbers of neutrons

Question 3

alpha particle

Answer 3

positively charged particle consisting of two protons and two neutrons

Question 4

anion

Answer 4

negatively charged atom or molecule

Question 5

atomic mass

Answer 5

average mass of atoms in an element

Question 6

Z / atomic number

Answer 6

number of protons in the nucleus of an atom

Question 7

cation

Answer 7

any positively charged atom or molecule

Question 8

electron

Answer 8

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

Question 9

empirical formula

Answer 9

the composition of a compound listed as the simplest whole number ratio of atoms

Question 10

fundamental unit of charge / elementary charge

Answer 10

equal to the charge of an electron: 1.602 x 10^-19

Question 11

ion

Answer 11

electrically charged atom or molecule - contains an unequal amount of protons and neutrons

Question 12

isomers

Answer 12

compounds with the same chemical formula but different structures

Question 13

law of constant composition

Answer 13

all samples of a pure compound contain the same elements in the same proportion by mass

Question 14

law of definite proportions

Answer 14

all samples of a pure compound contain the same elements in the same proportion 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

A / mass number

Answer 16

sum of protons and neutrons 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 of atoms of each element in a molecule of the compound

Question 18

neutron

Answer 18

uncharged subatomic particle located in the nucleus

Question 19

nucleus

Answer 19

positively charged center of an atom made up of protons and neutrons

Question 20

proton

Answer 20

positively charged subatomic particle located in the nucleus

Question 21

spatial isomers

Answer 21

compounds in which the orientations of the atoms in space differ

Question 22

structural formula

Answer 22

shows the atoms in a molecule and how they are connected

Question 23

structural isomer

Answer 23

one of two substances that have the same molecular formula but different physical and chemical properties because their atoms are bonded differently

Question 24

unified atomic mass unit

Answer 24

alternative unit to the atomic mass unit

Question 25

average atomic mass formula

Answer 25

(M1 * A1) + (M2 * A2) … / 100
may have many more factors; include all

Question 26

atomic mass unit

Answer 26

unit of mass equal to 1/12 of the mass of a 12C atom

Question 27

isotopic abundance

Answer 27

relative proportions of the stable isotopes of each element

Question 28

Avogadro’s number

Answer 28

6.022 x 10^23 mol^-1

Question 29

results of the Thomson experiment

Answer 29

Thomson proposed that cathode ray particles were negatively charged and subatomic. Cathode ray particles are now called electrons.

Question 30

results of the Millikan experiment

Answer 30

The charge of one electron is 1.6 x 10^-19 C

Question 31

results of the Rutherford experiment

Answer 31

most alpha particles passed through the gold foil, so they must have traveled through empty space inside the atom. Therefore, an atom is mostly empty space, with a positively charged nucleus at the center.