chemistry atoms test
a K atom differs from a K+ ion in that the K atom has one
more electron
hydrogen has three isotopes with mass numbers of 1, 2, and 3 and has an average atomic mass of 1.00794 amu. this information indicates that
more isotopes have an atomic mass of 1 than of 2 or 3
when a sodium atom reacts with a chlorine atom to form a compound, the electron configurations of the ions forming the compound are the same as those in which noble gas atoms?
neon and argon
the mass number of an atom is equal to the number of
neutrons plus protons
which two particles have approximately the same mass?
proton and neutron
the atomic number of an atom is always equal to the total number of
protons in the nucleus
as an Na atom forms an Na2+ ion, the number of protons in its nucleus
remains the same
what causes the emission of radiant energy that produces characteristic spectral lines?
return of electrons to lower energy levels
when the electrons of an excited atom return to a lower energy state, the energy emitted can result in the production of
spectra
in a sample of pure copper, all atoms have atomic numbers which are
the same and the atoms have the same number of electrons
what is the nuclear charge of an atom with a mass of 23 and an atomic number of 11?
11+
if eight electrons completely fill a principal energy level, what is the principal quantum number of the principal energy level?
2
as an electron in an atom falls to a lower energy level, the potential energy of the electron
decreases
if 75.0% of the isotopes of an element have a mass of 35.0 amu and 25.0% of the isotopes have a mass of 37.0 amu, what is the atomic mass of the element?
35.5 amu
how do you find the number of neutrons?
atomic mass - atomic number
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
the nucleus is the part of the atom that
contains most of the atom's total mass
a Ca2+ ion differs from a Ca0 atom in that the Ca2+ ion has
fewer electrons
how does the ground state electron configuration of the hydrogen atom differ from that of a ground state helium atom?
hydrogen contains a half-filled orbital
as an electron in an atom moves from the ground state to an excited state, the potential energy of the electron
increases