1. All About Atoms!

2. THE ATOM AN ATOM IS THE SMALLEST UNIT OF MATTER
IS THE “BUILDING BLOCK “OF ALL ELEMENTS
HAS THE SAME PROPERTIES AS THE ENTIRE ELEMENT
COMPOSED OF TWO PARTS:
1) A NUCLEUS IN THE CENTER
2) SHELLS/ORBITS SURROUNDING THE NUCLEUS
MADE UP OF 3 SUBATOMIC PARTICLES:
PROTONS
NEUTRONS
ELECTRONS

3. PROTONS (P+) NUMBER OF PROTONS = ATOMIC NUMBER
LARGE SUBATOMIC PARTICLE
FOUND IN THE NUCLEUS
HAS A POSITIVE CHARGE (+)
CONTRIBUTES TO MASS OF ATOM P+
NUMBER OF PROTONS = ATOMIC NUMBER

4. NEUTRONS (N0) PROTONS + NEUTRONS = ATOMIC MASS
LARGE SUBATOMIC PARTICLE
FOUND IN THE NUCLEUS OF AN ATOM
HAS A NEUTRAL CHARGE (ZERO, 0 CHARGE)
CONTRIBUTES TO MASS OF ATOM P+ N0
PROTONS + NEUTRONS = ATOMIC MASS

5. ELECTRONS (e-) PROTONS = ELECTRONS IN A NEUTRAL, OR BALANCED ATOM,
SMALL SUBATOMIC PARTICLE
FOUND IN SHELLS/ORBITS SURROUNDING THE NUCLEUS
HAS A NEGATIVE CHARGE (-)
DOES NOT CONTRIBUTE TO THE MASS OF THE ATOM
DETERMINES THE OVERALL CHARGE OF THE ATOM
electrons P+ N0
shells/orbits
IN A NEUTRAL, OR BALANCED ATOM,
PROTONS = ELECTRONS

6. 1st shell can hold up to 2 electrons
2nd shell can hold up to 8 electrons
3rd shell can hold up to 18 electrons

7. Bohr Model Bohr Model for Beryllium
Used to diagram atomic arrangement and particle placement
Model is one-dimensional even though real-life atoms are 3-D
4 P+
5N0
= electrons (e-)