Chapter 18 Review

This scientist published a detailed atomic
theory in 1808 based on evidence he
gathered through experiments with
gases. His atomic theory laid the
groundwork for later atomic models.
 John Dalton
British physicist Joseph John Thomson
was the first to identify the:
 electron
A common isotope of Carbon has a
mass number of 13. The total number of
protons in the nucleus would be:
The ____ is one kind of particle that
makes up the atom and carries a
positive charge. The neutron makes up
for “missing mass” and is found in the
nucleus. The third kind of particle carries
a ____ charge and has almost no mass.
 Proton
 Negative
Atoms with the same atomic number but
different atomic mass are called:
 isotopes
A – Atomic Number
 B – Chemical Symbol
 C – Name of Element
 D – Atomic mass
Fireworks contain different elements in
them for displaying different colors. The
different colors occur because:
 atoms of various elements emit light at
different frequencies
Elements in the same column on the
periodic table have similar chemical
reactivity because:
 they have the same number of valence
shell electrons
How many energy levels are filled in a
krypton atom?
 Four
A – Proton
 B – Neutron
 C – Nucleus
 D – Energy Level
 E -- Electron
 A chemical symbol represents the
_______________ of an element.
 Name
How many protons are in the atom of
the element above?
A certain atom has 26 protons, 26
electrons, and 30 neutrons. Its mass
number is ____.
 56
Describe where the electrons are in the
atom, where they have the least energy,
and where they have the most energy.
 Electrons go around the nucleus in a
cloud. Energy is lowest close to the
nucleus, and highest away from the
Use the periodic table to find the name,
atomic number, and the average
atomic mass of the following elements:
O, S.
O, oxygen, 8, 15.999
 S, sulfur, 16, 32.066
Who developed the first periodic table?
 Mendeleev