8/18/2019 C5 1The Composition of the Nucleus
1/2
The Composition Of The Nucleus
The Composition of the Nucleus
1. You have learn in chemistry that in an atom, electrons move
around a central core called the
nucleus.
2. The nucleus consists of protons and neutrons. It containing
almost all the mass of the atom.
3. The nucleus of an atom is very small compared to the size of
the atom
. !rotons and neutrons also "no#n as nucleons.
Nuclide Notation
1. !roton num$er is defined as the num$er of protons in a
nucleus.
2. Nucleon num$er is defined as the total num$er of protons and
neutrons in a nucleus. It is also
"no#n as mass num$er.
3. % nuclide is a type of atom #ith a particular proton and
nucleon num$er.
. % nuclide can $e represented $y a nuclide notation that sho#s
the sym$ol of element, proton
num$er and nucleon num$er.
&. 'igure $elo# sho#s the nuclide notation of a
nitrogen.
8/18/2019 C5 1The Composition of the Nucleus
2/2
Isotopes
1. Isotopes are atoms of certain elements #hich have the same
num$er of protons $ut different
num$er of neutrons in the nucleus of the atoms.
2. It can also $e defined as atoms of certain elements #ith the
same proton num$ers $ut #ith
different nucleon num$ers.
3. Isotopes have the same chemical properties $ut different
physical properties.
. Ta$le $elo# sho#s the proton and nucleon num$er of the
isotopes of hydrogen and o(ygen.
Element Name Symbol Proton
Number
Nucleon
Number
Number of
proton
Number of
neutron
Hydrogen Hydrogen 1 1 1 0
Deuterium 1 12 1 1
Tritium 1 23 1 2
Oxygen Oxygen-16 8 16 8 8
Oxygen-17 8 17 8 9
Oxygen-18 8 18 8 10
