1. Warm Up (11/3) What do atoms make up?
What do elements that are chemically combined make?
What do elements and compounds that are physically combined make?

2. ATOMS AND ATOMIC STRUCTURE Atom Nucleus Proton Neutron Electron

3. WHAT IS AN ATOM? The smallest unit of an element.
Consists of a central nucleus surrounded by one or more electrons.

4. WHAT IS THE NUCLEUS? The central part of an atom.
Composed of protons and neutrons.
Contains most of an atom's mass.

5. WHAT IS A PROTON? Positively charged particle.
Found within an atomic nucleus.

6. WHAT IS A NEUTRON?
Uncharged particle.
Found within an atomic nucleus.

7. WHAT IS AN ELECTRON? Negatively charged particle.
Located in shells that surround an atom's nucleus.

8. Valence Electrons
Found in the very last shell (farthest) from the nucleus

9. Shells 1st shell can hold up to 2 electrons
Every other shell can hold up to 8 electrons

10. Using the Periodic Table
Element symbol:
Consists of 1 uppercase letter or 1 uppercase and 1 lowercase letter
Ex) C is carbon; Ne is Neon

11. Using the Periodic Table
Atomic #
The WHOLE number listed for each element
Goes in order from left to right on the periodic table
Atomic # = # of protons AND # electrons for a neutral atom
Used to ID an element

12. Using the Periodic Table
Mass #
The DECIMAL listed for each element
Mass # = # of protons + # of neutrons in an atom

13. Calculating PEN To Find: Protons: use the atomic number
Electrons: use the atomic number
Neutrons
Mass # - Atomic #

14. Isotopes
Elements with the same number of protons (same element!) but a different number of neutrons
We know they are isotopes because they have different mass numbers!
Can write them as “element name-mass #”
Ex) Carbon-14 or Carbon-12

15. Isotope Notation
Charge (ion only)
Mass #
Atomic #
Element symbol