chem chapter 1
which quantity identifies an element?
atomic number
what is the total charge of nucleus of a nitrogen atom?
+7
an electron has a charge of
-1 and a smaller mass than a proton
atoms of the same element that have different numbers of neutrons are classified as
isotopes
subatomic particles can usually pass undeflected through an atom because the volume of an atom is composed of
largely empty space
the modern model of the atom is based on the work of
many scientist 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
compared to an electron in the first electron shel of an atom, an electron in the third shell of the same atom has
more energy
which subatomic particle has no charge
neutron
an atom of potassium-37 and an atom of potassium-42 differ in their total number of
neutrons
an atom is electrically neutral because the
number of protons equals the number of electrons
the gold foil experiment lead 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
which two particles have a mass approximately equal to one atomic mass unit?
proton and neutron
which two particles make up most of the mass of a hydrogen-2 atom?
proton and neutron
which particles are found in the nucleus of an atom
protons and neutrons
which subatomic particles are located in the nucleus of a neon atom
protons and neutrons
which subatomic particles are located in the nucleus of a neon atom?
protons and neutrons
all atoms of a given element must contain the same number of
protons plus neutrons
the atomic number of an atom is always equal to the number of its
protons, only
according to the electron-cloud model of the atom, an orbital is a
region of the most probable electron location
the light emitted from a flame is produced when electrons in the excited state
release energy as they move to lower energy states
the bright-line spectrum of sodium is produced when energy is
released as electrons move from higher to lower electron shells
what is the charge on a neutron?
0
what is the net charge of an ion that has 8 protons, 9 neutrons, and 10 electrons?
1+
what is the net charge of an atom with 9 protons, 11 neutrons, and 10 electrons?
1-
which electron configuration represents an atom in an excited state?
2-6-2
a 100.00-gram sample of naturally occurring boron contains 19.78 grams of boron-10 (atomic mass=10.01 atomic mass units) and 80.22 grams of boron-11 (atomic mass=11.01 atomic mass units). Which of the following numerical setups can be used to determine the atomic mass of natural occurring boron?
(0.1978)(10.01)+(0.8022)(11.01)
what is the total charge of the nucleus of a carbon atom?
+6
what is the total number of neutrons in an atom of O-18?
10
what is the total number of neutrons in an atom of an element that has a mass number of 19 and an atomic number of 9?
10
the mass of 12 protons is approximately equal to
12 atomic mass units
what is the mass number of an atom that has six protons, six electrons, and eight neutrons?
14
what is the total number of electrons in an atom of potassium?
19
the total mass of the protons in an atom of gold-198 is approximately
79 atomic mass units
in the wave-mechanical model, an orbital is a region of space in an atom where there is
a high probability of finding an electron
which statement best explains why most atomic masses on the periodic table are decimal numbers?
atomic masses are a weighted average of the naturally occurring isotopes
which of the following phrases describes an atom?
a negatively charged electron cloud surrounding a positively charged nucleus
which statement matches a subatomic particle with its charge?
a neutron has no charge
what was concluded about the structure of the atom as true result of the gold foil experiment?
a positively charged nucleus is surrounded mostly by empty space
the number of neutrons in the nucleus of an atom can be determined by
adding the atomic number to the mass number
which element has an atom in the ground state with a total of three valence electrons?
aluminum
a proton has a charge that is opposite the charge of
an electron
which of the following two particles have opposite charges
an electron and a proton
which statement is true about the charges assigned to an electron and a proton?
an electron is negative and a proton is positive
an atom of any element must contain
an equal number of protons and electrons
the region that is the most probable location of a electron in an atom is
an orbital
according to the wave mechanical model of the atom, electrons in an atom
are located in orbitals outside the nucleus
which value of an element is calculated using both the mass and the relative abundance of each of the naturally accruing isotopes?
atomic mass
all the isotopes of a given atom have
different mass numbers but the same atomic number
in the late 1800s, experiments using the cathode ray (thompson) tubes led to the discovery of the
electron
in a calcium atom in the ground state, the electrons that possess the least amount of energy are located in the
first electron shell
the modern model of the atom shows that electrons are
found in regions called orbitals
which statement describes how an atom in the ground state becomes excited?
the atom absorbs energy, and one or more electrons move to a higher electron shell
which statement compares the masses of two subatomic particles?
the mas of a proton is great than the mass of an electron
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 statement best describes electrons?
they are negative subatomic particles and are found surrounding the nucleus
the atomic mass of titanium is 47.88 atomic mass units. This atomic mass represents the
weighted average mass of all the naturally occurring isotopes of Ti
