SUBATOMIC PARTICLES

• atoms are the tiny units that makeup everything in our environment.
• Matter is anything that has mass and

  occupies space; however, matter cannot exist without atoms.
• Atoms comprise three types of particles: protons,

  neutrons, and electrons.
• Protons,Neutrons, and Electrons are called subatomic particles
• • A proton carries one positive electric charge

  (+1), represented by the symbol p

  +
• Protons is said to be stable by

  itself.
• The relative mass of a proton is 1.673x10-

  27 kg, equal to 1 atomic mass unit (amu).
• The neutron has no electrical charge. The symbol n0 represents it.
• Neutrons mass is

  approximately 1.675x10-27 kg, slightly greater than the proton's mass.
• Both protons and neutrons, called

  nucleons, make up the nucleus of an atom.
• The electron is the lightest of all the three subatomic particles.
• electron is so light that

  it has no great effect on the atom's mass.
• electrons mass is approximately 1,837 times smaller than the mass

  of the proton.
• It carries a net charge of negative one (-1) and is represented by the symbol e

  -

  .
• protons are found in the nucleus
• neutrons are found in the nucleus
• electrons are found in the electron shell/outside the nucleus.
• electron amu: 1/1 837
• the mass of an atom is concentrated in the nucleus, which means that it is based on

  the weight of protons and neutrons.
• all atoms are electrically neutral. An electrically neutral atom will always contain equal protons and

  electrons.
• atomic number is the number of protons.
• the symbol Z, serves as

  the "numerical identity" of an element.
• mass number of an atom refers to the total number

  of protons and neutrons (nucleons) in the atom.
• The mass

  number is represented by the symbol A.
• mass number (A) = number of protons + number of neutrons
• number of protons = number of electrons = atomic number (Z)
• number of neutrons = mass number (A) - atomic number (Z)