DAT GENERAL CHEMISTRY
QUESTIONS AND ANSWERS WITH
SOLUTIONS 2024
Atomic Number - ANSWER number of protons found in that atom; low number; (Z)
Mass Number - ANSWER Protons + Neutrons; high number; (A)
Atomic Mass - ANSWER relative mass of that atom compared to the mass of a carbon-12 atom (which is
set at 12.00); measured in amu;
1 amu = - ANSWER 1.66x10^-24
Atomic Weight - ANSWER weight (g) of one mole (mol) of a given element (g/mol); the weighted average
of all the masses (not the weights) of an element, weighted according to the natural abundance of the
isotopic species of an element
1mol = ______ (Avagadro's Number) - ANSWER 6.022x10^23 molecules
Isotope - ANSWER multiple species of an atom with same number of protons and a different number of
neutrons (different mass numbers); generally exhibit same chemical properties
Ernest Rutherford - ANSWER 1911; gave experimental evidence that an atom has a dense, positively
charged nucleus that accounts for a small portion of the volume of the atom
Max Planck - ANSWER developed first quantum theory; 1900; proposed that energy emitted as
electromagnetic radiation from matter comes in discrete bundles called quanta; E=hv (h-Planck's
constant)
Planck's constant - ANSWER 6.626x10^-34 J*s
,The Bohr Model of the Atom - ANSWER developed 1913 model of H atom using Rutherford and Planck's
findings; H atom has central proton, electron travels around it in a circular orbit; centripetal force acting
on the electron as it revolved around the nucleus was the electrical force between the positively charged
proton and negatively charged electron; quantized angular momentum so it changed in discrete
amounts in relation to the quantum number (L=nh/2pi) n=quantum number h=Planck's constant; from
this Energy of an electron: E=-Rh/n^2, Rh=Rydberg constant 2.18*10^-18 J/electron
Rydberg Constant - ANSWER 2.18 x 10^-18 J/electron
Smaller orbit of electron the... - ANSWER lower the energy state
What is the Bohr Model used for? - ANSWER used to explain the atomic emission spectrum and atomic
absorption spectrum of hydrogen; because these spectrum are not the continuous spectrum that
classical physics would expect, they are line spectrum
Balmer Series - ANSWER 4 spectral lines that appear in the visible light region when a hydrogen atom
undergoes a transition from energy levels n>2 to n=2.
Lyman Series - ANSWER Set of spectral lines appearing in the UV region when a hydrogen atom
undergoes a transition from energy levels n>1 to n=1.
Heisenberg Uncertainty Principle - ANSWER impossible to determine the momentum and position of an
electron simultaneously; means if the momentum of an electron is being measured accurately, its
position will change and vice-versa
Pauli exclusion principle - ANSWER no 2 electrons in any given atom can possess the same set of four
quantum numbers (n, l, ml, ms)
Energy state of an electron - ANSWER the position and energy of an electron described by its 4 quantum
numbers (n, l, ml, ms)
quantum number n - ANSWER "principal quantum number"; gives info about the size of the orbital;
bigger n is, the bigger the radius of the orbital, the bigger the energy of the orbital; Max number of
electrons in an energy level = 2n^2
, quantum number l - ANSWER "Azimuthal (angular momentum) quantum number"; gives info about the
shape of the orbital; value of l = 0 to n-1 ; l=0=s; l =1=p; l=2=d; l=3=f; Max number of electrons that can
exist in a subshell= 4l +2; greater the value of l, the higher the energy of the subshell, but subshell
energies from different principal energy levels may overlap
quantum number ml - ANSWER "Magnetic Quantum number"; gives info about the orientation of an
orbital; value of ml = l to -l (includes 0);
quantum number ms - ANSWER "Spin Quantum number"; there are two spin orientations: +1/2 and -
1/2; whenever electrons are in the same orbital they must have opposite spins
List the Order the Energy Levels Fill - ANSWER Rule: n+l, and if that is the same number, then the one
with the lower n will fill first; 1s, 2s, 2p, 3s,3p,4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f...etc
Hund's rule - ANSWER dictates which orbitals within a subshell fill first; within a given subshell, orbitals
are filled so that there is a maximum number of half-filled orbitals with parallel spins
Paramagnetic - ANSWER material has unpaired electrons, magnetic field aligns the spins of these
electrons and weakly attracts the atom
Diamagnetic - ANSWER materials have no unpaired electrons and are slightly repelled by a magnetic field
Which are the valence electrons for groups IA and IIA? - ANSWER the outermost s electrons
Which are the valence electrons for groups IIIA through VIIIA (remaining column on right, excluding
weird middle metals)? - ANSWER the outermost s and p electrons
Which are the valence electrons for the transition elements? - ANSWER the outermost s electrons and
the second to outermost d shell
Dmitri Mendeleev - ANSWER published first version of periodic table; showed elements ordered by
atomic weight, produced patter of similar properties
QUESTIONS AND ANSWERS WITH
SOLUTIONS 2024
Atomic Number - ANSWER number of protons found in that atom; low number; (Z)
Mass Number - ANSWER Protons + Neutrons; high number; (A)
Atomic Mass - ANSWER relative mass of that atom compared to the mass of a carbon-12 atom (which is
set at 12.00); measured in amu;
1 amu = - ANSWER 1.66x10^-24
Atomic Weight - ANSWER weight (g) of one mole (mol) of a given element (g/mol); the weighted average
of all the masses (not the weights) of an element, weighted according to the natural abundance of the
isotopic species of an element
1mol = ______ (Avagadro's Number) - ANSWER 6.022x10^23 molecules
Isotope - ANSWER multiple species of an atom with same number of protons and a different number of
neutrons (different mass numbers); generally exhibit same chemical properties
Ernest Rutherford - ANSWER 1911; gave experimental evidence that an atom has a dense, positively
charged nucleus that accounts for a small portion of the volume of the atom
Max Planck - ANSWER developed first quantum theory; 1900; proposed that energy emitted as
electromagnetic radiation from matter comes in discrete bundles called quanta; E=hv (h-Planck's
constant)
Planck's constant - ANSWER 6.626x10^-34 J*s
,The Bohr Model of the Atom - ANSWER developed 1913 model of H atom using Rutherford and Planck's
findings; H atom has central proton, electron travels around it in a circular orbit; centripetal force acting
on the electron as it revolved around the nucleus was the electrical force between the positively charged
proton and negatively charged electron; quantized angular momentum so it changed in discrete
amounts in relation to the quantum number (L=nh/2pi) n=quantum number h=Planck's constant; from
this Energy of an electron: E=-Rh/n^2, Rh=Rydberg constant 2.18*10^-18 J/electron
Rydberg Constant - ANSWER 2.18 x 10^-18 J/electron
Smaller orbit of electron the... - ANSWER lower the energy state
What is the Bohr Model used for? - ANSWER used to explain the atomic emission spectrum and atomic
absorption spectrum of hydrogen; because these spectrum are not the continuous spectrum that
classical physics would expect, they are line spectrum
Balmer Series - ANSWER 4 spectral lines that appear in the visible light region when a hydrogen atom
undergoes a transition from energy levels n>2 to n=2.
Lyman Series - ANSWER Set of spectral lines appearing in the UV region when a hydrogen atom
undergoes a transition from energy levels n>1 to n=1.
Heisenberg Uncertainty Principle - ANSWER impossible to determine the momentum and position of an
electron simultaneously; means if the momentum of an electron is being measured accurately, its
position will change and vice-versa
Pauli exclusion principle - ANSWER no 2 electrons in any given atom can possess the same set of four
quantum numbers (n, l, ml, ms)
Energy state of an electron - ANSWER the position and energy of an electron described by its 4 quantum
numbers (n, l, ml, ms)
quantum number n - ANSWER "principal quantum number"; gives info about the size of the orbital;
bigger n is, the bigger the radius of the orbital, the bigger the energy of the orbital; Max number of
electrons in an energy level = 2n^2
, quantum number l - ANSWER "Azimuthal (angular momentum) quantum number"; gives info about the
shape of the orbital; value of l = 0 to n-1 ; l=0=s; l =1=p; l=2=d; l=3=f; Max number of electrons that can
exist in a subshell= 4l +2; greater the value of l, the higher the energy of the subshell, but subshell
energies from different principal energy levels may overlap
quantum number ml - ANSWER "Magnetic Quantum number"; gives info about the orientation of an
orbital; value of ml = l to -l (includes 0);
quantum number ms - ANSWER "Spin Quantum number"; there are two spin orientations: +1/2 and -
1/2; whenever electrons are in the same orbital they must have opposite spins
List the Order the Energy Levels Fill - ANSWER Rule: n+l, and if that is the same number, then the one
with the lower n will fill first; 1s, 2s, 2p, 3s,3p,4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f...etc
Hund's rule - ANSWER dictates which orbitals within a subshell fill first; within a given subshell, orbitals
are filled so that there is a maximum number of half-filled orbitals with parallel spins
Paramagnetic - ANSWER material has unpaired electrons, magnetic field aligns the spins of these
electrons and weakly attracts the atom
Diamagnetic - ANSWER materials have no unpaired electrons and are slightly repelled by a magnetic field
Which are the valence electrons for groups IA and IIA? - ANSWER the outermost s electrons
Which are the valence electrons for groups IIIA through VIIIA (remaining column on right, excluding
weird middle metals)? - ANSWER the outermost s and p electrons
Which are the valence electrons for the transition elements? - ANSWER the outermost s electrons and
the second to outermost d shell
Dmitri Mendeleev - ANSWER published first version of periodic table; showed elements ordered by
atomic weight, produced patter of similar properties
