1. 2-1 The Nature of Matter Photo Credit: © John Conrad/CORBIS
Copyright Pearson Prentice Hall

2. 2-1 The Nature of Matter
Atoms The study of chemistry begins with the basic unit of matter, the atom.
Copyright Pearson Prentice Hall

3. 2-1 The Nature of Matter
Placed side by side, 100 million atoms would make a row only about 1 centimeter long. Atoms contain subatomic particles that are even smaller.
Copyright Pearson Prentice Hall

4. The subatomic particles that make up atoms are: protons neutrons
2-1 The Nature of Matter
The subatomic particles that make up atoms are:
protons
neutrons
electrons
Copyright Pearson Prentice Hall

5. 2-1 The Nature of Matter
Elements and Isotopes
A chemical element is a pure substance that consists entirely of one type of atom.
C stands for carbon.
Na stands for sodium.
Copyright Pearson Prentice Hall

6. 2-1 The Nature of Matter
The number of protons in an atom of an element is the element's atomic number.
Copyright Pearson Prentice Hall

7. 2-1 The Nature of Matter
Isotopes Atoms of the same element that differ in the number of neutrons they contain are known as isotopes.
Copyright Pearson Prentice Hall

8. 2-1 The Nature of Matter
Chemical Compounds A chemical compound is a substance formed by the chemical combination of two or more elements in definite proportions.
Copyright Pearson Prentice Hall

9. 2-1 The Nature of Matter
Chemical Bonds The atoms in compounds are held together by chemical bonds. The electrons that are available to form bonds are called valence electrons.
Copyright Pearson Prentice Hall

10. The main types of chemical bonds are: ionic bonds covalent bonds
2-1 The Nature of Matter
The main types of chemical bonds are:
ionic bonds
covalent bonds
Copyright Pearson Prentice Hall

11. 2-1 The Nature of Matter
Ionic Bonds
An ionic bond is formed when one or more electrons are transferred from one atom to another.
These positively and negatively charged atoms are known as ions.
Copyright Pearson Prentice Hall

12. 2-1 The Nature of Matter Sodium atom (Na) Sodium ion (Cl-)
Sodium ion (Na+)
Sodium atom (Cl)
The chemical bond in which electrons are transferred from one atom to another is called an ionic bond. The compound sodium chloride forms when sodium loses its valence electron to chlorine.
Protons
Electrons
Charge
Protons
Electrons
Charge
Protons
Electrons
Charge
Protons
Electrons
Charge
Copyright Pearson Prentice Hall

13. 2-1 The Nature of Matter
Covalent Bonds Sometimes electrons are shared by atoms instead of being transferred.
Copyright Pearson Prentice Hall

14. A covalent bond forms when electrons are shared between atoms.
2-1 The Nature of Matter
A covalent bond forms when electrons are shared between atoms.
single covalent bond
double bond
triple bond
Copyright Pearson Prentice Hall

15. Copyright Pearson Prentice Hall
2-1
The particles that move around the nucleus of an atom are called
neutrons.
protons.
electrons.
isotopes.
Copyright Pearson Prentice Hall

16. Copyright Pearson Prentice Hall
2-1
The atomic number of a carbon atom is 6. How many neutrons does the isotope carbon-14 have? 6 8 12 14
Copyright Pearson Prentice Hall

17. Copyright Pearson Prentice Hall
2-1
A chemical compound consists of
Electrons mixed with neutrons.
two or more elements combined in a definite proportion.
two or more protons combined in any proportion.
at least three elements combined by ionic or covalent bonds.
Copyright Pearson Prentice Hall