Topic: Element Identity and
Reactivity
Essential Question: What do the protons and
valence electrons determine about an
element?
Topic: Element Identity and Reactivity
Essential Question: What do the protons and valence
electrons determine about an element?
Protons
The number of protons is used to
identify an element
The atomic number on the periodic
table is the number of protons
For example: an atom of
Carbon has 6 protons
Topic: Element Identity and Reactivity
Essential Question: What do the protons and valence
electrons determine about an element?
Electrons
For atoms with a neutral charge,
the number of electrons equals the
number of protons.
For example:
Carbon has 6 protons
and 6 electrons
Topic: Element Identity and Reactivity
Essential Question: What do the protons and valence
electrons determine about an element?
Electron Shells
Each shell can hold
A certain number of
electrons
1st- 2 electrons
2nd- 8 electrons
3rd- 8 electrons
- - -
-
-
-
Nucleus
- -
- -
- -
Topic: Element Identity and Reactivity
Essential Question: What do the protons and valence
electrons determine about an element?
Valence Electrons
Valence electrons are the electrons located on the
outermost shell of an atom.
They determine the reactivity of an element.
This model shows that carbon has four valence
electrons.
Topic: Element Identity and Reactivity
Essential Question: What do the protons and valence
electrons determine about an element?
Valence electrons
Elements with 8 valence electrons are stable (will not react)
Elements with less than 8 valence electrons are reactive
For example, Sodium (Na), which has 1 valence
electron, reacts with Chlorine (Cl), which has 7 and
creates NaCl, which is table salt.
Na
Cl
Now take some time…
• Take 2 minutes to go over your notes and
highlight or underline the main ideas that
answer the essential question, you should not
highlight everything:
• What do the protons and valence electrons
determine about an element?
• Share with a neighbor, did you highlight the
same thing?
Time to use the left hand column
• You will now write your own questions using
the questioning verbs provided.
Topic: Element Identity and Reactivity
Essential Question: What do the protons and valence
electrons determine about an element?
Write a question
using one of the
following verbs:
Explain
Define
Protons
The number of protons is used to
identify an element
The atomic number on the periodic
table is the number of protons
For example: an atom of
Carbon has 6 protons
Topic: Element Identity and Reactivity
Essential Question: What do the protons and valence
electrons determine about an element?
Write a question
using one of the
following verbs:
Electrons
The number of electrons = the number
of protons
Explain
Define
For example:
Carbon has 6 protons
and 6 electrons
Topic: Element Identity and Reactivity
Essential Question: What do the protons and valence
electrons determine about an element?
Write a question
using one of the
following verbs:
Explain
Define
Electron Shells
Each shell can hold
A certain number of
electrons
1st- 2 electrons
2nd- 8 electrons
3rd- 8 electrons
- - -
-
-
-
Nucleus
- - -
- -
- -
Topic: Element Identity and Reactivity
Essential Question: What do the protons and valence
electrons determine about an element?
Write a question
using one of the
following verbs:
Valence Electrons
Electrons located on the outermost
shell of an atom
Explain
Define
They determine the reactivity of an
element
Topic: Element Identity and Reactivity
Essential Question: What do the protons and valence
electrons determine about an element?
Write a question
using one of the
following verbs:
Explain
Define
Valence electrons
Elements with 8 valence electrons are
stable (won’t react)
Elements with less than 8 valence
electrons are reactive
For example, Sodium, which has 1 valence electron,
reacts with Chlorine, which has 7 and creates NaCl,
which is table salt
Na
Cl
Now let’s write a summary
Look at each question you
wrote on your own, and
answer each question in a
complete sentence.