atomic number test

what is an ion ?

and atom or group of atoms that has an electric charge other than zero, created when an atom gains or loses electrons .

what is an isotope ?

atoms of the same element that have different numbers of nuetrons in the nucleus.

what is the atomic mass ?

average mass of all the known isotopes of an element .

what does the group number tell you about an element ?

elements with similar properties

what does the period number tell you about an element ?

elements with the same number of atomic or orbits .

what element group is highley inactive because they have a full set of valence electrons ?

noble gases

atoms of the same element can have different number of _____?

nuetrons

what is an orbit or energy level ?

one of the discrete allowed energies for electrons in an atom .

atoms of the same element have the same number of _______?

protons

what is the definition of an atom ?

smallest particle of an element that retains the chemical identity of an element.

what is the atomic number ?

the number of protons in the nucleus determines what element the atom represents .

what is the mass number ?

the number of protons plus the number of nuetrons in the nucleus .

what is the definition of a nucleus ?

tiny core at the center of an atom containing most of the atom's mass and all of its positive charge .

the nucleus has a charge of ______?

zero

the overall charge of an atom is ____ because the number of ______ equals the number of _____?

zero , protons , electrons .

what is the definition of a proton ?

A particle found in the nucleus with a positive charge exactly equal and opposite to the electron .

what is an element ?

A pure substance that cannot be broken down into simpler substances by physical or chemical means .

what is a compound ?

A substance that contains two or more different elements chemically joined and has the same composition throughout .

what is a molecule ?

a group of two or more atoms joined together by chemical bonds.

what is the definition of an electron ?

a particle with an electrical charge found inside of the Atomms but outside of the nucleus .

all of the elements in what group are radioactive ?

actinides