1. 2A.1 & 2A.2 Atoms and Elements
9/18/2017

2. Atom The basic building block for all matter in the universe.
Atoms fit together with other atoms to form matter.
Atoms make up all matter in the universe.

3. Atom Each atom is composed of 3 subatomic particles:
Protons
Neutrons
Electrons
The number of each atomic particle determines the properties of the atom.

4. Proton Positively charged Has the same mass as Neutrons
Located in the nucleus; tightly bound to neutrons

5. Neutron Has no charge (neutral) Has the same mass as Protons
Located in the nucleus; tightly bound to protons

6. Neutron Has no charge (neutral) Has the same mass as Protons
Located in the nucleus; tightly bound to protons

7. Electron
Negatively charged
Rotate in the space around the nucleus

8. History of the Atomic Model
1st Discovery: Democritus-Came up with the name atom; determined that atoms can not be divided.

9. History of the Atomic Model
2nd Discovery: Dalton-Theorized atoms are too small to be seen by the naked eye; came up with the Atomic Theory of Matter

10. History of the Atomic Model
3rd Discovery: Thompson-Used cathode ray to detect electrons and theorized that electrons were embedded in nuclei of atoms (Chocolate Chip Model)

11. History of the Atomic Model
4th Discovery: Rutherford-Theorized that atoms had a dense core which was a positive nucleus

12. History of the Atomic Model
5th Discovery: Bohr-Theorized electrons were orbiting the nucleus

13. Element
A substance whose elements all have the same number of protons in the nucleus.

14. Periodic Table Used to organize all elements
Every element has a square for each element that includes:
Element Name
Chemical/Element Symbol
Atomic Number
Atomic Mass

16. Element Name

17. Chemical/Element Symbol
Element Name
Chemical/Element Symbol

18. Chemical/Element Symbol
Each element has a different symbol
Symbols are written with one, two, or three letters
The first letter is always capitalized

19. Chemical/Element Symbol
Element Name
Atomic Number
Chemical/Element Symbol

20. Atomic Number
The atomic number of an element is equal to the number of protons that element’s atoms have.
The atomic number is a whole number
The atomic number is always the same for that element.
The elements on the periodic table are arranged numerically by increasing atomic number.

21. Chemical/Element Symbol
Element Name
Atomic Number
Chemical/Element Symbol
Atomic Mass

22. Atomic Mass
The atomic mass of an element is an average sum of the number of protons and the number of neutrons in the nucleus of an atom.
Atomic Mass is usually not a whole number.

23. Periods Families A horizontal row on the periodic table.
Vertical columns of elements on the periodic table.
They are numbered 1-18
Elements in the same family have similar properties
Also called Groups

24. Metalloids
Elements that have properties of both a metal and a nonmetal

25. Metals Majority of elements are metals.
Look back at your notes for the physical an chemical properties of notes.

26. Nonmetals