Chemistry Chapter 3

Question 1

number of protons in the atom

identifies the element

Answer 1

atomic number

Question 2

1=1.660 x^-27 kg
mass of proton and neutron =1
mass of electron= 0.0005

Answer 2

atomic mass unit AMU

Question 3

number of protons and neutrons

Answer 3

mass number

Question 4

atoms of the same element with a different atomic mass because of a different number of neutrons

Answer 4

isotopes

Question 5

isotopic notation of a nuclide

Answer 5

4 superscript- mass # protons + neutrons
2 subscript - protons
next to He

Question 6

mass number on periodic table is the ________________________- of the naturally occurring isotopes of an element

Answer 6

average atomic mass

Question 7

how do you calculate the average atomic mass

Answer 7

multiply the atomic mass of each isotope by the % in decimal form-> add the results together

Question 8

an atom is defined as the smallest part of an element that….

Answer 8

retains the chemical identity of that element

Question 9

the fact that carbon dioxide always contains 73 percent oxygen by mass is an illustration of

Answer 9

the law of constant composition/definite proportion

Question 10

a cathode ray consists of

Answer 10

electrons

Question 11

the electron was discovered by

Answer 11

thomson

Question 12

the scientist who measure the charge of the electron was

Answer 12

millikan

Question 13

the experiment that revealed the charge of the electron involved the use of

Answer 13

oil droplets

Question 14

rutherford called the core of the atom the

Answer 14

nucleus

Question 15

what makes up an atom (3)

Answer 15

electron
proton
neutron

Question 16

what is found on the outside of the nucleus of the atom

Answer 16

electron

Question 17

what is the approximate atomic mass of an neutron, in amu

Answer 17

1

Question 18

what is the approximate atomic mass of an electron in amu

Answer 18

essentially 0

Question 19

the atomic number of an atom is defined as its

Answer 19

number of protons

Question 20

the mass number of an atom is defined as its

Answer 20

total number of neutrons and protons

Question 21

an element’s identity is based on its

Answer 21

atomic number

Question 22

two atoms are isotopes if they contain

Answer 22

the same number of protons but different numbers of neutrons

Question 23

the symbol indicates a fluorine atom that contains
19 F
9

Answer 23

9 protons and 10 neutrons

Question 24

what did Democritus contribute to the understanding of matter

Answer 24

came up with the idea of the atom

Question 25

why were Democritus's ideas not accepted at the time

Answer 25

people believed Aristotle instead that everything is made up of earth water wind fire

Question 26

Why was Democritus's ideas reconsidered in the eighteenth century

Answer 26

experimental data, proved particles are made of different things

Question 27

Greek philosopher | idea of atom=indivisible, which was the foundation of the atomic theory

Answer 27

Democritus

Question 28

in a chemical reaction matter cannot be created or destroyed, it can only change form

Answer 28

law of conservation of mass

Question 29

a chemical compound contains the same elements in exactly the same proportion by mass regardless of the sample or source of the coumpound

Answer 29

law of definite proportion

Question 30

if two or more different compounds are composed of the same elements then the ratio of the masses of the elements is always a ratio of small whole numbers

Answer 30

law of multiple proportion

Question 31

part of _______- atomic theory 1. all matter is composed of ___________ 2. atoms of a given element are _________ in size, mass, and other properties; atoms of different elements __ in size, mass, and other properties 3. Atoms can't be ___ created or destroyed 4. Atoms of different elements combine in simple __________ to form _________ 5. in ________ atoms are combined, separated or rearrganged

Answer 31

Dalton's 1. extremely small particles called atoms 2. identical, differ 3. subdivided 4. whole number rations, chemical compounds 5. chemical reactions

Question 32

Modern atomic theory based on Dalton but modified All matter is composed of _____ atoms of any one element _______ from atoms of another element

Answer 32

atoms | differ in properties

Question 33

smallest part of an element that retains the properties of that element

Answer 33

atoms

Question 34

atoms contain

Answer 34

subatomic particles protons neutrons electrons

Question 35

electrons possess energy; travel in a straight line; cannot penetrate metal

Answer 35

crooke's tube/ cathode ray tube

Question 36

used a magnetic field around the cathode tube showed; electron affected by magnet concluded; all atoms contain e-; e- are negative: assumes positive matter must exist

Answer 36

J.J Thomson

Question 37

oil drop experiment determined the charge ( negative) on the e- calculated the mass of e- mass= 9.109x10^-31 kg

Answer 37

millikan

Question 38

Gold foil experiment showed nucleus is dense and positive: volume of nucleus very small compared to size of atom; e- actually occupy very little space but effectively occupy all the space outside the nucluse

Answer 38

rutherford

Question 39

proton has a charge= to the charge of the e- but opposite | proton=+1; e-=-1

Answer 39

composition of the nucleus

Question 40

positive charge mass=1.67x10^-27kg

Answer 40

proton

Question 41

neutral charge; mass=1.675x10^27kg

Answer 41

neutron

Question 42

protons should repel each other but when very close actually have a strong attraction; same attraction with neutron neutron forces, proton-neutron forces nuclear binding force (strong force)

Answer 42

forces in the nucleus