Phy Sci chapter four Flashcards

0
Q

What did Democritus suggest

A

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

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1
Q

Who came up with the first theory of atoms

A

Democritus

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2
Q

What did Dalton add to the atomic theory

A

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

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3
Q

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

A

Law of definite proportions

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4
Q

How did Thompson discover the electron

A

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

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5
Q

What model did Thomson develop

A

The plum pudding model

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6
Q

A subatomic a particle that has a negative charge

A

Electron

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7
Q

What is Rutherford’s atomic model

A

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

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8
Q

What experiment did Rutherford conduct

A

The gold-foil experiment

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9
Q

What part of the atom did Rutherford discover

A

Nucleus

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10
Q

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

A

Nucleus

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11
Q

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

A

Protons and electrons

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12
Q

This is how positive protons are attracted to negative electrons

A

Electric force

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13
Q

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

A

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

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14
Q

The number of protons in the nucleus of an atom

A

Atomic number

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15
Q

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

A

Mass number

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16
Q

Why do isotopes of the same element have different atomic masses

A

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

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17
Q

Unstable isotopes that emit radiation and decay into other isotopes

A

Radioisotopes

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18
Q

What formula is used to calculate the number of neutrons

A

Number of neutrons = mass number - atomic number

19
Q

What unit is used to express atomic mass

A

Unified atomic mass units

20
Q

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

A

Unified atomic mass unit

21
Q

What is the mole used for

A

Counting small particles

22
Q

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

A

Mole

23
Q

What is the abbreviation for mole

A

Mol

24
Q

What is one mole equal to

A

602,213,670,000,000,000,000,000 partic

6.022 x 1023

25
Q

What is the number for mole called

A

Avogadro’s number

26
Q

The mass in grams of one mole of a substance

A

Molar mass

27
Q

How do you find the amount of moles in an element

A

mass x 1 mol of element / molar mass of element

28
Q

How do you find the mass of moles in an element

A

amount x molar mass of element / 1 mol of element

29
Q

How do you find the molar mass go a compound

A

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

30
Q

What is the modern model of the atom

A

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

31
Q

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

A

Bohr’s

32
Q

How do electrons move to a higher energy level

A

They gain energy

33
Q

How do electrons move to a lower energy level

A

They lose energy

34
Q

What do electrons act like

A

Waves

35
Q

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

A

Orbital

36
Q

How are the energy levels of an atom filled

A

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

37
Q

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

A

Valence electrons

38
Q

What are the 4 types of orbitals

A

s
p
d
f

39
Q

How many electrons can each orbital hold

A

2

40
Q

What determines the number of electrons that each level can hold

A

Orbitals

41
Q

What makes an electron jump to a new energy level

A

When an atom gains or loses energy

42
Q

The lowest state of energy of an electron

A

Ground state

43
Q

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

A

Excited state

44
Q

A unit or quantum of light

A

Photon

45
Q

When does an electron release a photon

A

When it falls back to a lower level

46
Q

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

A

The wavelengths emitted by the element