Lesson 2 Subatomic particles

Atom: the smallest particle of an element

Subatomic Particles
Atoms are made up of three particles:
particle                   charge              mass                    location
proton (p)                                       +                               1 amu (u)                               nucleus
neutron (n)                           no charge               1 amu (u)                         nucleus
electron (e)                                      -                                 1/1836 amu (u)                   orbital   


amu: atomic mass unit - 1/12 the mass of a carbon atom

Nucleus: the dense positively charged central core of the atom

Orbital: a region in the atom where there is a high probability of locating an electron.




Atomic Number: number of protons in the nucleus (Bottom # on PT)
*identifies the element (like your SS#)

Mass number: total number of protons and neutrons in the nucleus (Top # on PT)

Nuclear Charge: (always +) equals atomic number (neutrons have no charge)

Isotopes: elements that have the same #p, but different #n (same element but different masses)

atomic mass: the average mass of all of the isotopes of an element

Net (overall) charge =  #p - #e
​All elements, as written, on the periodic table are neutral. This means that #p = #e

***If an atom does not have the same number of protons and electrons it is an ION and is positive (if it has more protons) or negative (if it has more electrons).