1. THE ATOM Chapter 6 – 2 Part 2

2. ISOTOPES
Isotopes are atoms that have the same number of protons, but have different numbers of neutrons.
Having a different number of neutrons gives the atom a different mass.

3. Isotopes of the same element are similar to one another in many ways.
Some elements have isotopes whose properties differ in important ways.

4. PROPERTIES OF ISOTOPES
Some isotopes of an element have special properties because they are unstable.
This type has a nucleus that will change over time.
These are radioactive because they will fall apart over time.
Most isotopes share most
of the same properties.

5. The Difference Between Isotopes
You can identify an isotope by its mass number.
The mass number is the number of protons and neutrons added together.
Compare these three carbon atoms to see how we determine the mass number for each.

6. NAMING ISOTOPES
To identify a specific isotope of an element, write the name of the element followed by a hyphen and the mass number.
Example:
Hydrogen – 2
Hydrogen - 3

7. Isotopes and Atomic Mass
Most elements contain a mixture of two or more isotopes with different #’s of neutrons.
The atomic mass of an element is the average of the masses of all the naturally occurring isotopes of that element.
This number is found on the element card on the periodic table. 6 C
12.01
ATOMIC MASS

8. Forces in Atoms
There are four basic forces acting between the particles in an atom that hold them together.
These forces work together to give an atom its structure and properties.

9. Gravitational Force
Gravitational force pulls objects towards one another.
The masses of the particles in atoms are so small, this force within atoms is very small.

10. Electromagnetic Force
Protons and electrons are attracted to each other because of this force.

11. STRONG FORCE
Protons push away from each other because they have the same charge.
The protons would fly apart if it wasn’t for strong force.

12. WEAK FORCE
The weak force is an important force in radioactive atoms.
In certain atoms, a neutron can change into a proton and an electron.
The weak force plays a big part in this change. +
NEUTRAL -

13. IONS
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons,

14. LET’S TRY IT!
TIME FOR THE
“MADE TO ORDER”
LAB