The document discusses the structure of atoms, including subatomic particles such as protons, neutrons, and electrons, and their roles in defining the properties of elements. It explains concepts like atomic number, isotopes, and energy levels of electrons, emphasizing the relationship between atomic structure and chemical reactivity. Additionally, it includes references to external resources for further learning.

1. ATOMS
THEIR STRUCTURE AND THE
PROPERTIES OF ELEMENTS
Miss Sofia Paz

2. MADE UP OF
SUBATOMIC
PARTICLES:
-PROTONS(+)
-NEUTRONS
-ELECTRONS(-)
First: Different elements or compounds have different properties:
States (luquid, solid, gas, plasma) this properties depend on the atoms of the
elements!
ATOM:
Smallest possible piece of an element (without loosing their
properties)

4. Electrons (-)
Protons (+)
Neutrons

5. The attraction of the
negatively charged
electrons and the
positively charged
protons keeps the
electrons close to
the nucleus.

6. How this subatomic particles form an ATOM?
-NUCLEOUS: NEUTRONS, PROTONS(+),
-CLOUD OF ELECTRONS (-)
The attraction of the
negatively charged
electrons and the
positively charged
protons keeps the
electrons close to
the nucleus.
Electrons have less
mass than neutrons
and protons.

7. NOT constantConstant
ATOMIC NUMBER (Z)( NUMBER OF PROTONS)
# of # of
The number of
protons is constant
in each element
The atom is
electrically neutral,
positive charges are
balanced with
the negative charges.
NO two
elements have
the same
atomic number
the number of protons = the Atomic Number(Z)

8. ISOTOPES (when the number of neutrons change)
Why C14, C13, C12??? Is the NUCLEAR NUMBER: NUMBER OF
PROTONS + NUMBER OF NEUTRONS
Alternate forms of elements (always same proton number but
different neutron number)

9. RADIOACTIVE ISOTOPE:
HOMEWORK FOR NEX CLASS! What are radioactive isotopes and What uses does they have?

10. ElECTRONS AND REACTIVITY:
Electrons properties: -amount of energy
-how thigly they are held by protons
Depending on this properties electrons belong to differents energy
leves:
I energy level can hold up to 2 electrons
II energy level can hold up to 8 electrons
III energy level can hold up to 18 electrons
HOW DOES ATOMS STRUCTURE DETERMINE HOW IT REACTS??

12. CONCEPT :CHEMICAL PROPERTIES ARE BASED ON STRUCTURE OF ATOMS
I energy level :2 electrons
II energy level: 8 electrons
III energy level : 18 electrons

13. CONCEPT :CHEMICAL PROPERTIES ARE BASED ON STRUCTURE OF ATOMS
Element/
isotope
Atomic
Number
Protons Neutrons Total electrons
(same number
ofprotons+)
12C 6
14C
14N 7
16O 8
P 15 15
S 16 16

14. Just howsmall is an atom??
• http://www.youtube.com/watch?v=yQP4UJhNn0I
• DOGS TEACHING CHEMSITRY
• http://www.youtube.com/watch?v=addK0b2Isw8