chapter 4: atomic structure

Question 1

Who was Democritus?

Answer 1

Among the first to suggest the existence of atoms

Question 2

What did Democritus believe?

Answer 2

Atoms were indivisible and indestructible

Question 3

Dalton’s atomic theory

Answer 3

• Discovers an atom using true science
• All elements are composed of tiny indivisible particles called atoms
• Atoms of the same element are identical
• Atoms of different elements combine in simple whole-number ratios to form chemical compounds
• In chemical reactions, atoms are combined, separated, or rearranged – but never changed into atoms of another element.
• Atoms cannot be broken down any further

Question 4

What are ions?

Answer 4

atoms with more or less electrons than protons

Question 5

Positive ions

Answer 5

cations

Question 6

Negative ions

Answer 6

anions

Question 7

Protons + neutrons =

Answer 7

atomic mass

Question 8

Number of protons equals…

Answer 8

atomic number

Question 9

How do we see atoms?

Answer 9

scanning(electron) tunneling microscope

Question 10

Who discovered the electron?

Answer 10

J.J. Thomson

Question 11

How did he discover the electron?

Answer 11

cathode ray tube, plum pudding model

Question 12

Who discovered the mass and charge of a electron?

Answer 12

Robert Millikan

Question 13

electron’s mass is…

Answer 13

about 2,000 time lighter than a proton or neutron

Question 14

How did he discover the mass and charge of a electron?

Answer 14

oil drop experiment

Question 15

Who discovered the proton?

Answer 15

Goldstein

Question 16

Who discovered the neutron?

Answer 16

Chadwick

Question 17

Who discovered the nucleus?

Answer 17

Rutherford

Question 18

How did he discover the nucleus?

Answer 18

gold foil experiment

Question 19

What did he discover about nucleus?

Answer 19

small, dense, positive

Question 20

What are atoms composed of?

Answer 20

identical protons, neutrons, & electrons

Question 21

How are atoms of one element different from another element?

Answer 21

they contain different numbers of PROTONS

Question 22

Atomic number symbol

Answer 22

Z

Question 23

Atoms of SAME element can have…

Answer 23

SAME number of protons but DIFFERENT number of neutrons

Question 24

What is an isotope?

Answer 24

• same element (same number of protons)
• DIFFERENT number of neutrons
• DIFFERENT mass number

Question 25

How do you find the number of neutrons?

Answer 25

Atomic mass number MINUS number of protons

Question 26

How do you find the mass #

Answer 26

protons + neutrons

Question 27

Negative

Answer 27

gained electrons

Question 28

Positive

Answer 28

lost electrons

Question 29

Where is the mass number on a symbol

Answer 29

top left corner

Question 30

Where is the atomic number on a symbol?

Answer 30

bottom left corner

Question 31

Hydrogen-1 (name)

Answer 31

Protium

Question 32

Hydrogen-1 (pro, elect, neu)

Answer 32

1 proton, 1 electron, 0 neutrons

Question 33

Hydrogen-2 (name)

Answer 33

deuterium

Question 34

Hydrogen-2 (pro, elect, neu)

Answer 34

1 proton, 1 electron, 1 neutron

Question 35

Hydrogen-3 (name)

Answer 35

tritium

Question 36

Hydrogen-3 (pro, elect, neu)

Answer 36

1 proton, 1 electron, 2 neutrons

Question 37

What is a proton?

Answer 37

positively charged subatomic particle

Question 38

What is a atom?

Answer 38

the smallest particle of an element that retains its identity in a chemical reaction

Question 39

mass number

Answer 39

the total number of protons and neutrons in the nucleus of an atom

Question 40

atomic mass unit (amu)

Answer 40

1/12 the mass of a carbon-12 atom

Question 41

electron

Answer 41

negatively charged subatomic particle

Question 42

atomic number

Answer 42

the number of protons in the nucleus of an element

Question 43

atomic number vs mass number

Answer 43

atomic = # of protons mass= protons+neutrons

Question 44

Average atomic mass or atomic weight

Answer 44

the weighted average mass of the atoms in a naturally occurring sample of an element

Question 45

period

Answer 45

horizontal row of periodic table

Question 46

group

Answer 46

vertical row of periodic table

Question 47

neutron

Answer 47

subatomic particle with no charge

Question 48

the nucleus of an atom is...

Answer 48

positively charged + high density

Question 49

Dalton's theory claimed atoms are indivisible

Answer 49

Scientists now know atoms are all divisible

Question 50

the number of neutrons in the nucleus of an atom can be calculated by

Answer 50

subtracting the number of protons from the mass number

Question 51

all atoms of the same element have the same...

Answer 51

of protons

Question 52

an atom of an element with atomic number 48 and mass number 120 contains

Answer 52

48 protons, 48 electrons, 72 neutrons

Question 53

the number 80 in the name bromine-80 represents

Answer 53

the mass number

Question 54

relative atomic masses are measured in

Answer 54

amus

Question 55

where is mass number?

Answer 55

after the name of the element

Question 56

particles in order from least massive to most massive

Answer 56

electron, proton, hydrogen atom, helium atom

Question 57

the identity of an element can be determined on the basis of?

Answer 57

the number of protons in an atom of the element

Question 58

the relative abundance of each isotope of an element determines it's

Answer 58

atomic mass