1. Bell Ringer
• Date: October 29th 2018
• Describe, in detail, the steps to
find the number of protons,
electrons and neutrons that are in
an atom of an element.
• Hint: The first step should
include the periodic table.
4. Atomic
Structure
• Atoms have a nucleus that contains
Protons and Neutrons
• Electrons are contained in
shells that surround the
nucleus
• An atom is made of mostly empty
space
• Protons have a positive (+) charge
• Electrons have a negative (-) charge
• Neutrons are Neutral
5.
6. Bohr Model
• Electrons in atoms are in orbits (shells) of differing energy
around the nucleus
• Bohr believed each electron orbit could only hold a set
number of electrons
• Once the level was full, additional electrons would be
bumped up to the next level
Orbit/ Shell
7.
8. • The number of electron shells with electrons is the same as (=) the
period number
1 Electron Shell
14. Bohr Diagrams
Find your element on the periodic table.
Determine the number of electrons – it is the same as the
atomic number.
This is how many electrons you will draw.
15. Bohr Diagrams
C
1) Draw a nucleus with
the element symbol
inside.
2) Carbon is in the 2nd
period, so it has two
energy levels, or shells.
3) Draw the shells around
the nucleus.
16. Bohr Diagrams
4) Add the electrons.
5) Carbon has 6
electrons.
6) The first shell can only
hold 2 electrons.
C
17. Bohr Diagrams
7) The 2nd shell can hold up
to 8 electrons.
8) Add 4 more electrons to
the 2nd shell
9) Count up the total # of
electrons to ensure it adds
up to the element’s
atomic number (in this
case 6)
C
18. Bohr Diagrams
• Only two electrons can
fit in the 1st shell.
• The 2nd shell can hold up
to 8 electrons.
• The 3rd shell can hold 18
electrons, but the
elements in the first few
periods only use 8
electrons.
C
