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