Atomic Structure Guided Notes
What is an Atom???
 Atoms are NOT indivisible! They CAN be broken down into smaller particles.
Subatomic Particle
Proton
Neutron
Electron
Charge
Mass
Location

Protons, neutrons and electrons are __________evenly distributed in an
Drawing of an Atom
atom.
 The protons and neutrons exist in a _________________ core at the center of
the atom. This is called the ___________________. The nucleus has a
_______________________ charge because the protons have a positive
charge and the ______________________ don’t have a charge!
 The _____________________________ are spread out around the edge of the
atom. They orbit the nucleus in layers called ____________________.
Electrons have a _________________________ charge.
 The ___________________ of an element contain equal numbers of protons and electrons and so have no overall
charge, so if you can find it on the Periodic Table, it means it has a charge of __________________!!!
Electrons

Atoms have no overall electrical charge and are ____________________.

This means atoms must have an equal number of ______________________ protons and
_________________
electrons.

The number of electrons is therefore the same as the ___________________ number.

Atomic number is the number of _______________________ rather than the number of electrons, because
atoms can lose or gain electrons but do not normally lose or gain protons.
I.
II.
III.
IV.
V.
VI.
What is an atom? Atom: ___________________________________________________
_______________________________________________________
Atomic Structure Atoms are composed of 2 regions: _____________: the center of the atom that contains the
mass of the atom ________________ ______________ : the region that surrounds the nucleus that contains
most of the space in the atom
What’s in the nucleus? The nucleus contains 2 of the 3 subatomic particles. ____________: positively charged
subatomic particles ____________: neutrally charged subatomic particles
What’s in the electron cloud? The ________ subatomic particle resides outside of the nucleus in the
__________ __________. Electron: the ____________ particle with a __________ charge and relatively no
__________.
How do these particles interact? Protons and neutrons live compacted in the tiny _______ charged nucleus
accounting for all of the ________ of the atom. The negatively charged _____________ are small and have
relatively no mass but occupy a large _____________ of space outside of the nucleus.
How do the subatomic particles balance each other? In an atom: ________________ = __________________
If ______ protons are present in an atom then _______ electrons are there to balance the overall charge of
the atom—atoms are _______________. The neutron has _____ charge therefore they do not have to equal
the number of protons or electrons.