Phy Sci chapter four

Question 0

What did Democritus suggest

Answer 0

He suggested that the universe was made of invisible units called atoms

Question 1

Who came up with the first theory of atoms

Answer 1

Democritus

Question 2

What did Dalton add to the atomic theory

Answer 2

That all atoms of a given element were exactly alike and atoms of different elements could join to form compounds

Question 3

A chemical compound always contains the same elements in exactly the same proportions by weight or mass

Answer 3

Law of definite proportions

Question 4

How did Thompson discover the electron

Answer 4

Thomson’s cathode-ray tube experiment suggested that cathode rays were made of negatively charged particles that came from inside atoms

Question 5

What model did Thomson develop

Answer 5

The plum pudding model

Question 6

A subatomic a particle that has a negative charge

Answer 6

Electron

Question 7

What is Rutherford’s atomic model

Answer 7

Rutherford proposed that most of the mass of he atom was concentrated at the atom’s center

Question 8

What experiment did Rutherford conduct

Answer 8

The gold-foil experiment

Question 9

What part of the atom did Rutherford discover

Answer 9

Nucleus

Question 10

An atom’s central region, which is made up of protons and neutrons

Answer 10

Nucleus

Question 11

What two particles are there an equal amount of in an atom

Answer 11

Protons and electrons

Question 12

This is how positive protons are attracted to negative electrons

Answer 12

Electric force

Question 13

What do atoms of an element have in common with other atoms of the same element

Answer 13

Atoms of each element have the same number of protons, but they can have different numbers of neutrons

Question 14

The number of protons in the nucleus of an atom

Answer 14

Atomic number

Question 15

The sum of the numbers of protons and a neutrons in the nucleus of an atom

Answer 15

Mass number

Question 16

Why do isotopes of the same element have different atomic masses

Answer 16

Isotopes of an element vary in mass because their number of neutrons differ

Question 17

Unstable isotopes that emit radiation and decay into other isotopes

Answer 17

Radioisotopes

Question 18

What formula is used to calculate the number of neutrons

Answer 18

Number of neutrons = mass number - atomic number

Question 19

What unit is used to express atomic mass

Answer 19

Unified atomic mass units

Question 20

A unit of mass that describes the mass of an atom or molecule

Answer 20

Unified atomic mass unit

Question 21

What is the mole used for

Answer 21

Counting small particles

Question 22

The SI base unit used to measure the amount of a substance whose number of particles is the same as the number of atoms of carbon in exactly 12g of carbon-12

Answer 22

Mole

Question 23

What is the abbreviation for mole

Answer 23

Mol

Question 24

What is one mole equal to

Answer 24

602,213,670,000,000,000,000,000 partic | 6.022 x 1023

Question 25

What is the number for mole called

Answer 25

Avogadro's number

Question 26

The mass in grams of one mole of a substance

Answer 26

Molar mass

Question 27

How do you find the amount of moles in an element

Answer 27

mass x 1 mol of element / molar mass of element

Question 28

How do you find the mass of moles in an element

Answer 28

amount x molar mass of element / 1 mol of element

Question 29

How do you find the molar mass go a compound

Answer 29

Add up the molar masses of all the atoms in a molecule of the compound

Question 30

What is the modern model of the atom

Answer 30

Electrons can be found only in certain energy levels, not between levels

Question 31

Who's model states that electrons can be in only certain energy levels

Answer 31

Bohr's

Question 32

How do electrons move to a higher energy level

Answer 32

They gain energy

Question 33

How do electrons move to a lower energy level

Answer 33

They lose energy

Question 34

What do electrons act like

Answer 34

Waves

Question 35

A region in an atom where there is a high probability of finding electrons

Answer 35

Orbital

Question 36

How are the energy levels of an atom filled

Answer 36

The number of energy levels that are filled in an atom depends on the number of electrons

Question 37

An electron yay is found in the outermost shell of an atom and that determines the atom's chemical properties

Answer 37

Valence electrons

Question 38

What are the 4 types of orbitals

Answer 38

s p d f

Question 39

How many electrons can each orbital hold

Answer 39

2

Question 40

What determines the number of electrons that each level can hold

Answer 40

Orbitals

Question 41

What makes an electron jump to a new energy level

Answer 41

When an atom gains or loses energy

Question 42

The lowest state of energy of an electron

Answer 42

Ground state

Question 43

An electron gains energy by absorbing a photon so it moves to an

Answer 43

Excited state

Question 44

A unit or quantum of light

Answer 44

Photon

Question 45

When does an electron release a photon

Answer 45

When it falls back to a lower level

Question 46

What is a type of "atomic fingerprint" that can be used to identify the substance

Answer 46

The wavelengths emitted by the element