1. The Atom & Isotopes
Packet #5
Chapter #2

2. Introduction to Atoms & Elements
The smallest particle of an element
**Elements are composed of atoms
Element
A substance composed of atoms having an identical number of protons in each nucleus.
A substance that cannot be decomposed into simpler substances
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3. Structure of Atom Two “broad” regions Interior Exterior Nucleus
Electron Shell
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4. Structure of Atom II Nucleus Interior part of the atom that contains
Protons
Have a positive charge
Neutrons
Have a neutral charge (no charge)
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5. Structure of Atom III Electron Shell/Cloud
Exterior region of the atom where electrons are found
Electrons
Negative charge
Surround the atom
The most outer electrons are used in the formation of chemical bonds.
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6. The Periodic Chart

7. The Periodic Chart The Periodic Chart
Is a list of all elements, but more importantly, it lists the characteristics of the atoms that make up each element.
The list provides the number of protons, the atomic number, and the atomic mass of the atom found within a particular element.

8. The Periodic Chart & Elements The Equation
The Periodic Chart shows the atomic number and atomic mass of the elements
Atomic Number (Z)
The number of protons in the nucleus of an atom
Atomic Mass (A)
The absolute atomic mass of an atom
Equation
A = Z + N
N = number of neutrons in the nucleus of an atom
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9. Isotopes

10. Isotopes One of two or more atoms with very similar properties.
An isotope is an atom that has the same atomic number but a different atomic mass.
In order to change the atomic mass, if the atomic number is the same, then the number of neutrons must be changed.

11. Isotopes Isotopes are used to help prove the theory of evolution.
Carbon-14 dating.

12. Review

13. Review Atom Interior Protons Positive Charge Neutrons Neutral Charge
Exterior
Electrons
Negative Charge
Helps make chemical bonds
Remember, an element is composed of similar atoms
A = Z + N

14. Review II Isotopes Used to support theory of evolution
Atoms with same atomic number
Atoms with different atomic mass
Used to support theory of evolution