1. Section 2.1 What three subatomic particles make up atoms?
Where are those particles located?
What charge does each carry?
How are all of the isotopes of an element similar?   Different?
What are the two main types of chemical bonds?

2. 2.1 Vocabulary
atom ionic bond nucleus ion electron covalent bond element molecule isotope van der Waals forces compound

3. Chapter 2 The Chemistry of Life
Atoms – the building blocks of matter
(100 million atoms side by side = 1 cm in length)
Subatomic particles in the atom:
1. Protons Inside the _____________
2. Neutrons
3. Electrons

5. Neutrons = ________charge Electron = ________ charge
Protons = _____ charge
Neutrons = ________charge
Electron = ________ charge
Protons and neutrons about the same mass
Electron is very small (1/1840 mass of proton)
Electrons in constant motion around the nucleus

6. Elements in the human body
# Protons = # electrons
Overall charge of atom is ________________
Proton # also called the _______________
____________________.

7. Elements
Pure substance Made of one type of atom More than 100, but only about 25 in living organisms

8. The Periodic Table of Elements
Interactive

9. Isotopes
Atoms of the same element but a different number of ___________
Identified by their mass number example:
All isotopes of an element have the same chemical properties because same number of ________________

11. Radioactive Isotopes
Nuclei are ______________ and break down at a constant rate over time
Important scientific/practical uses
Geologists determine age of rocks and fossils
Treat cancer
Kill bacteria that cause food to spoil
Labels (tracers) to follow movements of substances in organisms

12. Chemical Compounds
Substance formed by the chemical combination of ____________________
Combine in definite proportions
Use chemical formulas to identify them _________________
Physical and chemical properties of a compound are _____________ from the elements making it up

13. Chemical Bonds Bonding involves the electrons in the atoms
Ionic Bond forms when electrons are transferred from one atom to another
__________-an atom that loses electrons, positive charge
__________-an atom that gains electrons, negative charge

14. Ionic Bond
NaCl

15. Covalent Bond
H2O

16. Covalent Bonds Electrons are shared between atoms
Single bond ______ electrons shared
Double bond ______ electrons shared
Triple bond _______ electrons shared
Molecule- smallest unit of most compounds
-formed when atoms bond covalently

17. van der Waals forces Intermolecular forces of attraction
Molecules get close together and attraction develops between oppositely charged regions of nearby molecules

18. Gecko
Gecko’s foot covered by half a million tiny hairs
Comes in contact with a large area of the wall at molecular level