Ch 3 Section 2

Question 1

Atom

Answer 1

Smallest particle of an element that retains the chemical properties of that element

Question 2

All atoms consist of

Answer 2

2 regions

Question 3

Nucleus

Answer 3

Very small region at the center of an atom

Question 4

Nucleus is made up of at least one

Answer 4

Positively charged particle called a proton and usually one or more neutral particles called neutrons

Question 5

Surrounding the nucleus is a region occupied by

Answer 5

Negatively charged particles called electrons

Question 6

Electrons region is very

Answer 6

Large compared with nucleus

Question 7

Subatomic particles

Answer 7

Proton
Neutron
Election

Question 8

First discovery of a subatomic particle resulted from investigations into

Answer 8

Relationship between electricity and matter

Question 9

Many experiments performed in which electric current was passed

Answer 9

Through various gases at low pressures

Question 10

As scientific advances allowed a deeper exploration of matter it became clear that atoms are actually composed of several basic types of

Answer 10

Smaller particles and that the number and arrangement of these particles determine that atoms chemical properties

Question 11

Those experiments carried out in

Answer 11

Cathode ray tubes

Question 12

When current was passed through a cathode ray tube surface of tube

Answer 12

Directly opposite the cathode glowed

Question 13

Hypothesized that glow was caused by a

Answer 13

Stream of particles, a cathode ray

Question 14

Ray traveled from cathode to

Answer 14

Anode when current was passed through the tube

Question 15

Cathode Rays were deflected by a

Answer 15

Magnetic field in the same manner as a wire carrying electric current which is know to have negative charge

Question 16

Rays were deflected

Answer 16

Away from a negatively charged object

Question 17

Observations led to hypothesis that particles that commode cathode Rays are

Answer 17

Negatively charged

Question 18

Cathode ray hypothesis supported by

Answer 18

JJ thomsons experiments

Question 19

Thomson was able to measure the ratio of the charge of

Answer 19

Cathode Ray particles to their mass and found that ratio was always the same

Question 20

Thomson concluded that all cathode Rays are composed of

Answer 20

Identical negatively charged particles called electrons

Question 21

Cathode Rays have identical properties regardless of the

Answer 21

Element used to produce them

Question 22

Concluded that electrons are present in

Answer 22

Atoms of all elements

Question 23

Cathode ray experiments provided evidence that atoms are

Answer 23

Divisible and that one of an atoms basic constituents is the electron

Question 24

Thomsons experiment revealed that the electron has a very large

Answer 24

Charge to mass ratio

Question 25

Robert a Millikan measured

Answer 25

The charge of the electron

Question 26

Scientists used the charge of the electron and the charge to mass ratio of the electron to determine that an electrons mass is about

Answer 26

1/2000 the mass of the simplest type of hydrogen atom

Question 27

Simplest type of hydrogen atom

Answer 27

Smallest atom known

Question 28

Electron actually has a mass of

Answer 28

1/1837 the mass of the simplest hydrogen atom

Question 29

Because atoms are electrically neutral they must contain a

Answer 29

Positive charge to balance the negative electrons

Question 30

Because electrons have so much less mass than atoms atoms must contain

Answer 30

Other particles that account for most of their mass

Question 31

Thomson proposed the plum pudding model-> negative electrons were spread evenly throughout the

Answer 31

Positive charge of the rest of the atom

Question 32

Ernest Rutherford, Hans greiger, and Ernest mars den bombarded a thin piece of

Answer 32

Gold foil with fast moving alpha particles

Question 33

Alpha particles are positively charged particles with about

Answer 33

4x the mass of a hydrogen atom

Question 34

Greiger and marsden assumed that mass and charge were

Answer 34

Uniformly districts throughout atoms of gold foil

Question 35

Expected alpha particles to pass through with only a slight

Answer 35

Deflection and for vast majority of particles that was the case

Question 36

When they checked for the possibility of wide angle deflections they found that approx

Answer 36

1 in 8000 alpha particles were deflected back toward the source

Question 37

Rutherford reasoned that deflected alpha particles must have experienced some

Answer 37

Powerful force within the atom

Question 38

Rutherford concluded that the force must be caused by a very densely packed

Answer 38

Bundle of matter with a positive electric charge, the nucleus

Question 39

Rutherford discovered that volume of nucleus was very

Answer 39

Small compared with total volume of an atom

Question 40

Niels Bohr proposed a model in which electrons

Answer 40

Surrounded the positively charged nucleus

Question 41

Except for the nucleus of the simplest type of hydrogen atom all atomic nuclei are made of

Answer 41

Protons and neutrons

Question 42

A proton has a positive charge equal in

Answer 42

Magnitude to the negative charge of an electron

Question 43

Atoms are electrically neutral because they contain

Answer 43

Equal numbers of protons and electrons

Question 44

Neutrons are

Answer 44

Electrically neutral

Question 45

Simplest hydrogen atom consists of a single

Answer 45

Proton nucleus with a single electron moving about it

Question 46

A proton has a mass 1836 times greater than

Answer 46

That of an electron

Question 47

The nuclei of atoms of different elements differ in their number of

Answer 47

Protons and thus in the amount of positive charge they possess

Question 48

Number of protons determines

Answer 48

Atoms identity

Question 49

Particles other than electrons protons and neutrons have little

Answer 49

Effect on the chemical properties of matter

Question 50

Generally particles that have the same electric charge

Answer 50

Repel one another

Question 51

When 2 protons are extremely close to each other there is a strong

Answer 51

Attraction between them

Question 52

As many as ---- protons can exist

Answer 52

83 protons can exist close together to help form a stable nucleus

Question 53

Nuclear forces: short Range

Answer 53

Proton-neutron, proton-proton, and neutron-neutron forces that hold nuclear particles together

Question 54

Electron cloud: region occupied by

Answer 54

Electrons, cloud of negative charge

Question 55

Radius of an atom is the distance from

Answer 55

Center of the nucleus to the outer portion of the electron cloud

Question 56

Because atomic radii are so small they are expressed using

Answer 56

The pico meter (pm)

Question 57

Atomic radio range from about

Answer 57

49 to 270 pm

Question 58

Nuclei of atoms have radiu about

Answer 58

.001 pm and incredibly high densities (2 x 10^8 metric tons per cm^3)