Chem test 1

A 100.00-gram s ample of naturally occurring boron contains 29) Which s ubatomic particle has no charge? 19.78 grams of boron-10 (atomic mas s = 10.01 atomic mas s units ) and 80.22 grams of boron-11 (atomic mas s = 11.01 atomic mas s units ). W hich of the following numerical s etups can be us ed to determine the atomic mas s of naturally occurring boron?

2) (0.1978)(10.01) + (0.8022)(11.01)

Chlorine-37 can be represented as

37 17 Cl

What is the total number of valence electrons in an atom of sulfur in the ground state?

6

Which two notations repres ent different is otopes of the s ame element?

6 4 Be and 9 4 Be

What was concluded about the s tructure of the atom as the result of the gold foil experiment?

A positively charged nucleus is surrounded by mostly empty space.

Which statement describes the distribution of charge in an atom?

A positively charged nucleus is surrounded by one or more negativetly charged electrons.

What was concluded about the structure of the atom as the result of the gold foil experiment?

A positively charges nucleus is surrounded by mostly empty space

Which conclusion was a direct result of the gold foil experiment

An atom is mostly empty space with a dense positively charged nucleus

Which s tatement is true about the charges as s igned to an Electron and a proton

An electron is a negative and a proton is a positive

The region that is the mos t probable location of an electron in an atom is

An orbital

Which s tatement best explains why mos t atomic mas s es on the Periodic Table are decimal numbers ?

Atomic mas s es are a weighted average of the naturally occurring isotopes .

As a result of the gold foil experiment, it was concluded that an atom..?

Contains a small, demse nucleus

The modern model of the atom s hows that electrons are

Found in regions called orbitals

Which group of atomic models is listed in historical order from the earliest to the most recent?

Hard-sphere model, electron-shell model, wave-mechanical model

Which model correctly describes the locations of protons and electrons in the wave-mechanical model of the atom..?

In the nucleus (location of protons)regions of most probable location(location of electrons)

who shot a cathode ray at the atom

J.J Thompson

who came up with "plum pudding model"

J.J. Thompson

The gold foil experiment led to the conclusion that each atom in the foil was composed mostly of empty space because most alpha particles directed at the foil..

Passed through the foil

Who came up with the gold foil experiment

Rutherford

Compared to the entire atom, the nucleus of the atom is..?

Smaller and contains most of the atoms mass

What did J.J. Thompson believe about the mass of an atom

That it was evenly distributed within the defense core and electrons were embedded throughout (chocolate chip cookie)

Which s tatement correctly des cribes the charge of the nucleus and the charge of the electron cloud of an atom?

The nucleus is pos itive and the electron cloud is negative.

Which statement correctly describes the charge of the nucleus and the charge of the electron cloud of an atom

The nucleus is positive and the electron cloud is negative

Which s tatement best des cribes electrons ?

They are negative subamatic particles and are found surrounding the nucleus

In the wave-mechanical model, an orbital is a region of s pace in an atom where there is

a high probability of finding an electron

simplest element building blocks of matter

an atom

A proton has a charge that is opposite the charge of..?

an electron

An orbital of an atom is defined as the most probable location of..?

an electron

who came up with the planetary model

bohr

what is the charge and mass of a proton

charge: +1 mass: 1amu

what is the charge and mass of an electron

charge: -1 mass: 0amu

what is the charge and mass of an neutron

charge: 0 mass: 1amu

All the is otopes of a given atom have

different mass numbers but the s ame atomic number

In the late 1800s, experiments using cathode ray tubes led to the discovery of the..?

electron

negatively (-1) charged particle, with ZERO mass

electron

was discovered by J.J. Thompson in cathode experiment

electron

electrons are found in orbitals:regions of most probable location of an electron

electron cloud model

what is daltons model

hard sphere model(atom appeared as just a dense hard solid sphere)

Which group of atomic models is listed in historical order from the earliest to the most recent?

hard-s phere model, electron-s hell model, wave- mechanical model

How did Thompson conclude that the atom was negatively charged

hot a cathode ray at the atom and it was deflected in a certain way

two elements that have the same atomic number but different atomic masses

isotopes

Subatomic particles can us ually pas s undeflected through an atom becaus e the volume of an atom is compos ed of

largely empty s pace

According to the wave-mechanical model of the atom electrons in an atom are..?

located in orbitals outside the nucleus

The modern model of the atom is based on the work of

many s cientis ts over a long period of time

The atomic mass of an element is calculated using the

masses and the ratios of its naturally occurring isotopes

Anything that has mass and volume(solid, liquid, gas)

matter

What happened during the gold foil experiment

most of the particles went directly though the gold foil with a small amount deflecting back

Which s ubatomic particle has no charge?

neutron

neutral particle (zero charge) with a mass of 1-amu

neutron

what is bohrs model

planetary model(he introduced electron shells around nucleus)

what is J.J. Thompsons model

plum pudding (discovered the electron)

What is rutherfords model

positive small nucleus surrounded by mostly empty space (introduced the concept of empty space)

positively (+1) charged particle with a mass of 1-amu

proton

All atoms of a given element mus t contain the s ame number of

protons

The atomic number of an atom is always equal to the number of its

protons , only

Which particles are found in the nucleus of an atom?

protons and neutrons

Which s ubatomic particles are located in the nucleus of a neon atom(same for any atom)?

protons and neutrons

According to the electron-cloud model of the atom, an orbital is a

region of the mos t probable electron location

who shot alpha particles (positively (+)) charged particles at the atoms of a gold foil

rutherford

The number of neutrons in the nucleus of an atom can be determined by

subtracting the atomic number from the mas s number

Which seaquence represents a correct order of historical developments leading to the modern model of the atom?

the atom is a hard sphere---->most of the atom is empty space--->electrons exist in orbitals outside the nucleus

what is wave mechanical model

the electron cloud(electrons are in most probable locations called orbitals)

what is the planetary model

visual of the atom which had the nucleus as a small dense center and the rings of electrons orbiting the nucleus

Experiments performed to reveal the structure of atoms led scientists to conclude that an atoms..?

volume is mainly unoccupied(empty space)

Not found in fixed orbits around a nucleus

wave-mechanical model

An electron has a charge of...?

-1 and a s maller mas s than a proton

what are Rutherfords conclusions

1- atom is composed mostly of "empty space" 2-atom has a small dense positive center (nucleus)

What is the total number of neutrons in an atom of an element that has a mas s number of 19 and an atomic number

10

What is the mass number of the nuclear symbol 19 9 F ?

19

What is the total number of protons in the nucleus of an Atom of potassium-42

19

The nucleus of an atom of K-42 contains

19 protons and 23 neutrons