Unit 5: Atoms and Subatomic Particles

Question 1

Dalton’s Atomic Theory (3)

Answer 1

atoms are tiny particles that make up matter

atoms of an element are similar and different from other elements

in a chemical reaction atoms of two or more elements combine

Question 2

Atomic Size

Answer 2

SMALLEST PARTICLE of an element that retains the PROPERTIES of that element

Question 3

What are the three subatomic particles?

Answer 3

protons, electrons, neutrons

Question 4

Like charges _____ and unlike charges _____

Answer 4

REPEL…..ATTRACT

Question 5

What charge do protons have?

Answer 5

positive (+ve)

Question 6

What charge does electrons have?

Answer 6

negative charge (-ve)

Question 7

What charge do neutrons have?

Answer 7

neutral (0 charge)

Question 8

Rutherford’s Gold-Foil experiment

Answer 8

+vely charged particles were aimed at atoms of gold

most went through the atoms

some were reflected occasionally

Question 9

What was the theory at the time of Rutherford’s Gold-Foil Experiment?

Answer 9

charges (positive and negative) were distributed evenly throughout

the atom plum pudding model

Question 10

Plum pudding model

Answer 10

the model that indicates charges within an atom as evenly distributed

not a lot of empty space in the atom

Question 11

Who discovered electrons and when?

Answer 11

JJ Thompson in 1897

Question 12

How did JJ Thompson discover electrons

Answer 12

passed an electric current through gas at low pressure, sealed in tubes with electrodes at either end

rays attracted to metal plates with a +ve charge and repelled by metal plates with a -ve charge.

he figured the ray was made up of -vely charged particles

electrons (e-)

Question 13

Atoms are electrically….

Answer 13

neutral

Question 14

What must equal what?

Answer 14

negative charge must = positive charge

Question 15

Who discovered protons?

Answer 15

Goldstein in 1886

Question 16

How did Goldstein discover protons

Answer 16

found rays traveling in opposite direction from cathode (Thompson’s) rays (e-)

Question 17

What did Goldstein discover

Answer 17

particles that traveled in the opposite direction were protons

Question 18

Organize the subatomic particles by weight lightest to heaviest

Answer 18

electron, proton, neutron

Question 19

Who confirmed the existence of neutrons and when?

Answer 19

Chadwick in 1932

Question 20

What did Chadwick discover?

Answer 20

confirmed the existence of neutrons

other info ab neutrons…

neutrons had no charge and a mass almost equal to mass of p+

Question 21

Structure of an atom

Answer 21

nucleus that contains protons and neutrons

electrons are located in a large, empty space around the nucleus

Question 22

Atomic Mass Unit (amu)

Answer 22

1/12 of the mass of the carbon-12 atom

Question 23

What is the mass of a proton?

Answer 23

about 1 (1.007) amu

Question 24

What subatomic particle has a mass of about 1 (1.007) amu?

Answer 24

proton

Question 25

What is the mass of a neutron?

Answer 25

about 1 (1.008) amu

Question 26

What subatomic particles has a mass of about 1 (1.008) amu?

Answer 26

neutron

Question 27

What is the mass of an electron?

Answer 27

0.000549 amu

Question 28

What subatomic particle has a mass of 0.000549 amu?

Answer 28

electron

Question 29

What is found outside the nucleus?

Answer 29

electron

Question 30

What is found inside the nucleus?

Answer 30

protons and neutrons

Question 31

How are atoms different?

Answer 31

the number of protons is unique to each atom

Question 32

Properties of Atomic Number (4)

Answer 32

specific for each element same for all atoms of an element equal to the protons in an atom appears above the symbol of an element

Question 33

If an atom of an element is electrically neutron...

Answer 33

the net charge of an atom is 0

Question 34

When the net charge of an atom is 0...

Answer 34

the atom of the element is electrically neutron

Question 35

An atom has an equal number of what?

Answer 35

protons and neutrons + electrons | idk what im saying

Question 36

Mass Number

Answer 36

represents the number of particles in the nucleus

Question 37

What is the mass number equal to?

Answer 37

number of protons + number of neutrons

Question 38

If zinc has a mass number of 65 and an atomic number of 30 how many neutrons are in the zinc atom?

Answer 38

35

Question 39

Isotope

Answer 39

atoms of the same element that have the same number of protons, but different numbers of neutrons

Question 40

What does a nuclear symbol represent?

Answer 40

a particular ATOM of an element

Question 41

Where is the atomic number and atomic mass located on a nuclear symbol?

Answer 41

Atomic Number: top left Atomic Mass: bottom left

Question 42

What is atomic mass the average of?

Answer 42

weighted average of masses for each individual isotope of an element

Question 43

atomic mass

Answer 43

the mass of an atom (protons + neutrons)

Question 44

atomic number

Answer 44

the number of protons in the nucleus

Question 45

How are atoms of the same element alike?

Answer 45

same number of protons

Question 46

Isotope average atomic mass calculation:

Answer 46

atomic mass = (mass 1 × %1) + (mass 2 × %2 ) +...and so on

Question 47

Isotope average atomic mass calculation for PERCENTAGE/ABUNDANCE

Answer 47

atomic mass = (mass 1 × x) + (mass 2 × [1-x] )

Question 48

What is a Bohr model?

Answer 48

a circle (nucleus) where protons and neutrons are located with rings around the nucleus where electrons are located

Question 49

How does the Bohr model help us understand atoms?

Answer 49

helps us understand where the electrons lie within the atom

Question 50

Who discovered that atoms were mostly empty space?

Answer 50

Rutherford

Question 51

What were Rutherford's conclusions to the Gold-Foil experiment?

Answer 51

atom is mostly empty space there is a positive charge in the center (center is called the nucleus)